electronic supplementary information for: beta-oligofurans · s1 electronic supplementary...

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Electronic Supplementary Information for:

beta-Oligofurans

Thomas Fallon,a Anthony C. Willis,‡a A. David Rae,‡a Michael N. Paddon-Row*b

and Michael S. Sherburn*a

aResearch School of Chemistry, Australian National University, Canberra, ACT 0200 (Australia)

bSchool of Chemistry, The University of New South Wales, Sydney, NSW 2052 (Australia)

E-mail: [email protected] (synthetic)

E-mail: [email protected] (computational) ‡Correspondence authors for crystallographic data ([email protected] and

[email protected])

Electronic Supplementary Material (ESI) for Chemical ScienceThis journal is © The Royal Society of Chemistry 2012

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CONTENTS

1 EXPERIMENTAL SECTION......................................................................................................................................... 3

1.1 GENERAL METHODS .................................................................................................................................................. 3

1.2 SYNTHESIS OF FURANS 6–28...................................................................................................................................... 3

1.3 LITHIUM/HALOGEN EXCHANGE SELECTIVITY EXPERIMENTS ...........................................................................18

2 REFERENCES ................................................................................................................................................................22

3 ANISOTROPIC DISPLACEMENT ELLIPSOID PLOTS......................................................................................23

4 UV-VIS SPECTRA OF DIBROMO-OLIGOFURANS AND CYCLIC OLIGOFURANS.................................27

5 1H AND 13C NMR SPECTRA .......................................................................................................................................29

6 COMPUTATIONAL DATA..........................................................................................................................................73

6.1 THE ACYCLIC SERIES OF BETA-OLIGOFURANS.....................................................................................................73

6.2 THE CYCLIC SERIES ...............................................................................................................................................109


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1 Experimental Section

1.1 General Methods 1H NMR spectra were recorded at 800 MHz, 600 MHz, 400 MHz and 300 MHz using a Bruker

AVANCE 800, Bruker AVANCE 600, Varian 400 or Varian Mercury 300 spectrometer. Residual

chloroform (δ 7.26 ppm) was used as the internal reference for 1H NMR spectra recorded in this

solvent. Coupling constants (J) are quoted to the nearest 0.1 Hz. 13C NMR spectra were recorded at

200 MHz, 150 MHz, 100 MHz or 75 MHz using a Bruker AVANCE 800, Bruker AVANCE 600,

Varian 400 or Varian Mercury 300 spectrometer. The central line of the deuterochloroform signal

(δ 77.1 ppm) was used as an internal reference for 13C NMR spectra recorded in this solvent.

Assignment of carbon signals was assisted by DEPT or HSQC experiments. IR spectra were

recorded on a Perkin–Elmer Spectrum One spectrometer as thin films on sodium chloride plates for

oils or as potassium bromide discs for solid products. Mass spectra were recorded on a Finnigan

PolarisQ mass spectrometer using electron impact (EI+) ionisation mode at 70 eV for low-resolution

mass spectra. High-resolution mass spectra were recorded using VG Autospec operating at 70 eV.

Melting points were measured on a Reichert melting point stage and are uncorrected. Analytical

thin layer chromatography was performed using Merck silica gel plates, pre-coated with silica gel

60 F243 (0.2 mm). Flash chromatography employed 230–400 mesh silica gel. Preparative HPLC

was performed using a Waters 600E instrument. Reactions were conducted under a positive

pressure of dry argon or nitrogen in oven dried glassware. Diethyl ether (Et2O) and tetrahydrofuran

(THF) were dried over sodium wire and distilled from sodium benzophenone ketyl. Petrol refers to

40–60 °C petroleum spirits unless otherwise stated. Commercially available chemicals were

purified by standard procedures or used as purchased.

1.2 Synthesis of Furans 6–28

Dibromobifuran 6

O

Br Br

O

O

BrBr

nBuLi 1.0 equiv.CuCl2 1.1 equiv.

Et2O -78 °C to RT59%

4 6X-ray

Dibromobifuran 6 was prepared by a modified literature procedure:1 To a solution 3,4-

dibromofuran 4 (20.0 g, 88.54 mmol) in Et2O (350 mL) at –78 °C was slowly added n-butyllithium


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(1.54 M in hexanes, 57.5 mL, 88.54 mmol, 1.0 mol equiv) and the resulting solution was stirred for

30 min. Dry CuCl2 (13.1 g, 97.4 mmol, 1.1 mol equiv) was added in one portion. The mixture was

stirred at –78 °C for 30 min then allowed to warm to RT and stirred for 1 hour. The reaction

mixture was poured into a rapidly stirring mixture of diethyl ether (300 mL) and water (300 mL).

The resulting suspension was filtered through celite, washed with water and then brine. The organic

phase was dried over MgSO4 and the solvent was removed in vacuo. The resulting residue was

subjected to flash chromatography on silica gel eluting with petroleum spirits to give the title

compound as white crystalline solid (7.67 g, 59%) from which crystals suitable for single crystal

X-ray diffraction analysis were obtained. Rf = 0.73 (petroleum spirits); mp 75–78 °C (petroleum

spirits); νmax (KBr)/cm–1 3144, 3121, 2958, 2930, 1721, 1642, 1586, 1529, and 1493; δH/ppm (400

MHz; CDCl3) 7.87 (2H, d, J 1.0 Hz) 7.52 (2H, d, J 1.0 Hz); δC/ppm (100 MHz; CDCl3) 141.8 (CH),

141.0 (CH), 116.1 (C), 100.8 (C); UV-Vis (MeCN) λmax 200 nm (ε = 10000); MS (70eV, EI): m/z

(%): 293.9 ([M81Br81Br]+, 45), 291.9 ([M79Br81Br]+, 100), 289.9 ([M79Br79Br]+, 54), 262.9 (13), 183.0

(23); HRMS: calcd for C8H6O279Br81Br [M]+: 291.8558; found 291.8552.

Dibromotetrafuran 8

O

O

BrBr

O

O

Br

O

O

Br

nBuLi 1.0 equiv.CuCl2 1.1 equiv.Et2O, -78 °C to RT50%

6 8X-ray

To a solution of dibromobifuran 6 (1.168 g, 4.00 mmol) in Et2O (60 mL) at –78 °C was slowly

added n-butyllithium (2.86 mL of a 1.40 M solution in hexanes, 4.00 mmol, 1.0 mol equiv) and the

solution was stirred for 30 min. To the resulting mixture was added solid CuCl2 (592 mg, 4.40

mmol, 1.1 mol equiv) in one portion. The mixture was stirred at –78 °C for 30 min then allowed to

warm to ambient temperature and stirred for 1.5 h. The reaction mixture was poured into a rapidly

stirring mixture of diethyl ether (50 mL) and water (50 mL). The resulting suspension was filtered

through celite, washed with water (2 × 100 mL), brine (2 × 50 mL), dried over magnesium sulphate

and the solvent was evaporated under reduced pressure at ambient temperature. The resulting

residue was subjected to flash chromatography on SiO2 eluting with petroleum ether to give the title

compound as a white powder (425 mg, 50%). A sample was recrystallised from

dichloromethane/petroleum spirits to give crystals suitable for single crystal X-ray analysis. Rf =

0.26 (petroleum ether); mp 72 °C (dichloromethane/petroleum spirits); νmax (film)/cm–1 3151, 1764,

1530 and 1492; δH/ppm (300 MHz; CDCl3) 7.90 (2H, d, J 1.8 Hz) 7.43 (2H, d, J 1.8 Hz) 7.38 (2H,


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d, J 1.8 Hz) 7.06 (2H, d, J 1.8 Hz); δC/ppm (75 MHz; CDCl3) 141.5 (CH), 141.3 (CH), 141.1 (CH),

140.3 (CH), 117.1 (C), 115.5 (C) 115.5 (C), 100.8 (C); UV-Vis (MeCN) λmax 199 nm (ε = 23000);

MS (70eV, EI): m/z (%): 425.8 ([M81Br81Br]+, 12), 423.8 (24, [M81Br79Br]+), 421.8 ([M79Br79Br]+,

12), 394.8 (22), 345.0 (100), 342.9 (100), 150.0 (55); HRMS: calcd for C16H8O479Br81Br [M]+:

423.8769; found 423.8770.

3-Bromo-4-boronpinacolatofuran 11

4 11

O

Bri) nBuLi 1.1 equiv.iPrO3B 1.5 equiv.Et2O -78°C to RT

O

B OO

ii) pinacol 1.0 equiv.MgSO4, CH2Cl293% over 2 steps

BrBr

To a stirred solution of 3,4-dibromofuran 4 (12.2 g, 54.0 mmol) in THF (250 mL) at –78 °C was

slowly added a solution of n-butyllithium in hexanes (1.59 M, 37 mL, 59.0 mmol, 1.1 mol equiv).

The solution was allowed to stir at –78 °C for 10 min before by the drop-wise addition of tri-

isopropylborate (18.7 mL, 81 mmol, 1.5 mol equiv). The solution was allowed to warm to RT over

30 min and then quenched with water, diluted with diethyl ether (250 mL), washed with 1 N HCl

(200 mL), water (2 × 200 mL) and brine (200 mL). The aqueous phase was extracted with diethyl

ether (100 mL) and washed with brine (50 mL). The combined organic layers were dried over

magnesium sulfate and the solvent removed in vacuo. The residue was dissolved in

dichloromethane (300 mL) and to this was added pinacol (6.38 g, 54.0 mmol, 1.0 mol equiv) and

anhydrous magnesium sulfate (5 g). The flask was equipped with a drying tube and the solution was

stirred overnight at RT then passed through a short plug of silica and the solvent removed in vacuo

to give the title compound as light orange solid (13.7g, 93%). Mp 45–46 °C (dichloromethane); νmax

(KBr)/cm–1 3165, 3140, 2982, 2932, 2868, 1634, 1558, 1525, 1510, 1472, 1454, 1436 and 1406;

δH/ppm (300 MHz; CDCl3) 7.67 (1H, dd, J 1.5 and 0.3 Hz) 7.46 (1H, dd, J 1.5 and 0.3 Hz) 1.32

(12H, s); δC/ppm (75 MHz; CDCl3) 152.1 (CH), 141.8 (CH), 103.9 (C), 83.8 (C), 24.0 (CH3) (C–B

signal absent); MS (70eV, EI): m/z (%): 274.0 ([M81Br]+, 29), 272.0 ([M79Br]+, 30), 257.0 (20),

193.1 (31), 172.9 (30), 45 (100); HRMS: calcd for C10H14B79BrO3 [M]+: 272.0219; found 272.0215.

3,4-Diiodofuran 15

3,4-Diiodofuran 15 was prepared using an unpublished procedure developed by Trauner2 and is

reproduced here, with minor modifications, by permission. To a 500 mL three-neck flask fitted with


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a mechanical stirrer, a water cooled condenser, and a 100 mL dropping funnel was added

2,3-diiodo-2-butene-1,4-diol (10.0 g, 29.4 mmol), followed by N-methyl-2-pyrrolidinone (125 mL)

and hexanes (200 mL). The mixture was stirred vigorously and heated to 85 °C. To this was added a

preheated (85 °C) solution of K2Cr2O7 (8.65 g, 29.4 mmol) in H2SO4 (3 M, 37 mL) drop-wise in

portions (ca. 6 mL per portion) over 2 h. The biphasic mixture was allowed to stir at 85 °C for 5 h

and then allowed to cool to room temperature. The hexane layer was decanted off and the remaining

liquid was extracted once with hexanes (100 mL). The hexane layers were combined, and washed

with water (2 × 50 mL) then saturated Na2S2O3 (50 mL) until the purple colouration was removed.

The organic phase was then washed with brine (50 mL), dried over MgSO4, passed though a short

plug of silica gel, and concentrated in vacuo to yield the title compound as a colourless oil (2.17 g,

23%). Rf = 0.8 (hexane); 1H NMR (300 MHz, CDCl3): δH/ppm 7.45 (s, 2H), consistent with that

previously reoprted.3

Dibromotrifuran 16

O

II

15

O

B OO

Br

O

OO

Br Br

16

2.1 equiv.

Ag2CO3 4.2 equiv.Pd(PPh3)4 5 mol%11

THF, reflux, 15 min, 53%

3,4-Diiodofuran 15 (509 mg, 1.59 mmol), furan 11 (912 mg, 3.34 mmol, 2.1 mol equiv), silver

carbonate (1.84 g, 6.3 mmol, 4.2 mol equiv) and tetrakis(triphenylphosphine)palladium (92 mg,

0.075 mmol, 0.05 mol equiv) were combined in a flask. The vessel was fitted with a septum cap and

evacuated (ca. 1 mmHg) then placed under at atmosphere of argon for a total of 3 cycles. Dry,

degassed THF (5 mL) was added and the stirred solution heated to reflux for 15 minutes. The

reaction mixture was allowed to cool to ambient temperature then was passed through a short plug

of flash silica, washing with diethyl ether. The solvent was removed from the filtrate under reduced

pressure and the residue was subjected to flash chromatography on silica gel, eluting with hexane,

to give the title compound as a yellow oil (304 mg, 53%). Rf = 0.22 (hexane); νmax (film)/cm–1 3381,

2923, 2854, 1954, 1767, 1492 and 1461; δH/ppm (300 MHz; CDCl3) 7.68 (2H, s), 7.43 (2H, s), 7.20

(2H, s); δC/ppm (75 MHz; CDCl3) 141.8 (CH), 141.5 (CH), 140.9 (CH), 117.5 (C), 114.8 (C), 101.8

(C); UV-Vis (MeCN) λmax 197 nm (ε = 9800); MS (70eV, EI): m/z (%): 359.8 ([M81Br81Br]+, 11),


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357.8 ([M81Br79Br]+, 22), 355.8 ([M79Br79Br]+, 11), 328.9 (10), 278.9 (100), 277.0 (92), 251.9 (21),

248.9 (23), 195.0 (78); HRMS: calcd for C12H681Br79BrO3 [M]+: 357.8663; found 357.8660.

Diiodotrifuran 17

O

O

I

O

I

O

O

Br

O

BrnBuLi 2.1 equiv.I2 2.2 equiv.

Et2O, -78 °C, 98%

16 17X-ray

To a solution of dibromotrifuran 16 (604 mg, 1.69 mmol) in diethyl ether (20 mL) at –78 °C was

slowly added a solution of n-butyllithium in hexanes (1.59 M, 2.23 mL, 3.54 mmol, 2.1 mol equiv).

The solution was stirred at –78 °C for 10 min then a solution of iodine (942 mg, 3.71 mmol, 2.2 mol

equiv) in diethyl ether (10 mL) was added drop-wise. The end-point of the reaction can be observed

when a red/brown colour persists. The solution was stirred at –78 °C for a further 5 min then

quenched with saturated aqueous sodium thiosulfate solution. After allowing to warm to room

temperature, the solution was diluted with diethyl ether and washed with water and then brine. The

ethereal layer was dried over magnesium sulfate and the solvent was removed under reduced

pressure to give the title compound as a yellow oil (751 mg, 98%). An analytical sample was

obtained by crystallisation from hexane to give a white crystalline solid from which crystals

suitable for single crystal X-ray analysis were obtained. Mp 71 °C (hexane); νmax (KBr)/cm–1 3142,

2923, 1612, 1489, 1326 and 1310; δH/ppm (300 MHz; CDCl3) 7.75 (2H, s) 7.48 (2H, d, J 1.8 Hz),

7.22 (2H, d, J 1.8 Hz); δC/ppm (75 MHz; CDCl3) 146.4 (CH), 141.2 (CH), 140.8 (CH), 119.8 (C),

115.9 (C), 69.4 (C); MS (70eV, EI): m/z (%): 451.8 ([M]+, 10), 324.9 (97), 198.0 (100); HRMS:

calcd for C12H6I2O3 [M]+: 451.8406; found 481.8405.

Dibromopentafuran 18

O

O

I

O

I

O

O

Br

O

O

O

Br

17

O

B OO

Br2.2 equiv.



18X-ray


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A flask was charged with diiodo-trifuran 17 (300 mg, 0.664 mmol), bifunctional furan 11 (399 mg,

1.46 mmol, 2.2 mol equiv), silver carbonate (805 mg, 2.92 mmol, 4.4 mol equiv) and Pd(PPh3)4 (38

mg, 0.033 mmol, 0.05 mol equiv). The vessel was fitted with a septum cap and evacuated (ca. 1

mmHg) then placed under at atmosphere of argon for a total of 3 cycles. Dry, degassed THF (2.4

mL) was added and the stirred solution heated to reflux for 15 minutes. The reaction mixture was

cooled then passed through a short plug of flash silica, washing with diethyl ether. The solvent was

removed from filtrate under reduced pressure and the residue was subjected to flash

chromatography on silica gel, eluting with 15% toluene in hexane, to give dibromo-pentafuran 18

as a white solid (173 mg, 53%). Recrystallisation from dichloromethane/hexane gave crystals

suitable for single crystal X-ray analysis. Mp: 67 – 70 °C; Rf 0.27 (15% toluene/hexane);

νmax(KBr)/cm-1 3150, 1765, 1493, 1337 and 1216; δH/ppm (300MHz; CDCl3) 7.68 (2H, d, J 1.8

Hz), 7.42 (2H, d, J 1.8 Hz), 7.35 (2H, s), 7.22 (2H, d, J 1.2 Hz), 7.15 (2H, d, J 1.5 Hz); δC/ppm

(75MHz; CDCl3) 141.6 (CH), 141.3 (CH), 141.1 (CH), 140.8 (CH), 140.7 (CH), 117.5 (C), 116.4

(C), 116.1 (C), 114.8 (C), 101.6 (C); UV-Vis (MeCN) λmax 195nm (ε = 33000); MS (70eV, EI): m/z

(%): 489.9 (20, [M (81Br79Br)]+), 460.9 (54), 409.0 (100), 189.1 (74); HRMS: calcd for

C20H1081Br79BrO5 [M]+: 489.8874; found 489.8862.

Diiodopentafuran 19

O

O

I

O

O

O

InBuLi 2.1 equiv.I2 2.2 equiv.

Et2O, -78 °C, 91%

O

O

Br

O

O

O

Br

18 19

To a solution of dibromopentafuran 18 (144 mg, 0.293 mmol) in diethyl ether (3.5 mL) at –78 °C

was slowly added a solution of n-butyllithium in hexanes (1.59 M, 0.388 mL, 0.616 mmol, 2.1 mol

equiv). The solution was stirred at –78 °C for 10 min and then a solution of iodine (164 mg, 0.646

mmol, 2.2 mol equiv) in diethyl ether (2 mL) was added drop-wise. The end-point of the reaction

can be observed when a red/brown colour persists. The solution was stirred at –78 °C for a further 5

min then quenched with saturated aqueous sodium thiosulfate solution. After allowing to warm to

room temperature, the solution was diluted with diethyl ether and washed with water then brine.

The ethereal layer was dried over magnesium sulfate and the solvent was removed under reduced

pressure to give the title compound as a yellow oil (155 mg, 91%). νmax (film)/cm–1 3142, 2939,

2851, 1860, 1774 and 1491; δH/ppm (300 MHz; CDCl3) 7.69 (2H, d, J 1.2 Hz), 7.44 (2H, d, J 1.8

Hz), 7.30 (2H, s), 7.23 (2H, d, J 1.2 Hz), 7.14 (2H, d, J 1.8 Hz); δC/ppm (75 MHz; CDCl3) 146.2


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(CH), 141.2 (CH), 141.0 (CH), 140.7 (CH), 140.7 (CH), 119.9 (C), 116.3 (C), 116.3 (C), 115.8 (C),

69.2 (C); MS (70eV, EI): m/z (%): 583.9 ([M]+, 31), 554.9 (42), 457.0 (100), 189.1 (32), HRMS:

calcd for C20H10I2O5 [M]+: 583.8618; found 583.8621.

Dibromoheptafuran 20

O

O

I

O

O

O

I

O

O

O

OO

OO

Br BrO

B OO

Br2.2 equiv.



20X-ray

19

3,4-Diiodopentafuran 19 (47 mg, 0.0805 mmol), furan 11 (48 mg, 0.177 mmol, 2.2 mol equiv),

silver carbonate (98 mg, 0.354 mmol, 4.4 mol equiv) and tetrakis(triphenylphosphine)palladium (5

mg, 0.004 mmol, 0.05 mol equiv) were combined in a flask. The vessel was fitted with a septum

cap and evacuated (ca. 1 mmHg) then placed under at atmosphere of argon for a total of 3 cycles.

Dry, degassed THF (0.35 mL) was added and the stirred solution heated to reflux for 15 minutes.

The reaction mixture was cooled then passed through a short plug of flash silica, washing with

diethyl ether. The solvent was removed from filtrate under reduced pressure and the residue was

subjected to flash chromatography on silica gel, eluting with 5% diethyl ether in hexane, to give the

title compound as a white solid (22 mg, 42%). Recrystallisation from dichloromethane/hexane

afforded crystals suitable for single crystal X-ray diffraction analysis. Mp 136–137 °C

(dichloromethane/hexane); νmax (KBr)/cm–1 3148, 2957, 2925, 2870, 1767, 1728, 1619, 1494 and

1458; δH/ppm (400 MHz; CDCl3) 7.74 (2H, d, J 2.0 Hz), 7.43 (2H, d, J 1.6 Hz), 7.31 (2H, d, J 1.6

Hz), 7.23 (2H, d, J 1.6 Hz), 7.19 (2H, d, J 1.6 Hz), 7.10 (2H, s), 7.08 (2H, d, J 2.0 Hz); δC/ppm (100

MHz; CDCl3) 141.6 (CH), 141.2 (CH), 140.9 (CH), 140.9 (CH), 140.9 (CH), 140.7 (CH), 140.6

(CH), 117.5 (C), 116.5 (C), 116.2 (C), 116.1 (C), 116.0 (C), 115.1 (C), 101.5 (C); UV-Vis (MeCN)

λmax 195 nm (ε = 35000); MS (70eV, EI): m/z (%): 623.9 ([M81Br81Br]+, 26), 621.9 ([M81Br79Br]+,

49), 619.9 ([M79Br79Br]+, 25), 592.8 (100), 542.9 (58), 263.1 (66), 131.7 (61); HRMS: calcd for

C28H1481Br79BrO7 [M]+: 621.9086; found 621.9085.


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Diiodotetrafuran 21

nBuLi 2.1 equiv.I2 2.2 equiv.

Et2O, -78 °C, 99%O

O

Br

O

O

Br

O

O

I

O

O

I

8 21

To a solution of dibromotetrafuran 8 (213 mg, 0.503 mmol) in diethyl ether (6 mL) at –78 °C was

slowly added a solution of n-butyllithium in hexanes (1.59 M, 0.66 mL, 1.06 mmol, 2.1 mol equiv).

The solution was stirred at –78 °C for 10 min and then a solution of iodine (281 mg, 1.11 mmol, 2.2

mol equiv) in diethyl ether (4 mL) was added drop-wise. The end-point of the reaction can be

observed when a red/brown colour persists. The solution was stirred at –78 °C for a further 5 min

then quenched with saturated aqueous sodium thiosulfate solution. After allowing to warm to room

temperature, the solution was diluted with diethyl ether and washed with water then brine. The


pressure to give the title compound as a yellow solid (257 mg, 99%). Mp 86 °C (hexane); νmax

(KBr)/cm–1 3163, 3138, 1620, 1584, 1567, 1541, 1527, 1508 and 1493; δH/ppm (400 MHz; CDCl3)

7.77 (2H, d, J 1.6 Hz), 7.40 (2H, d, J 1.6 Hz), 7.39 (2H, d, J 1.6 Hz), 7.08 (2H, d, J 1.6 Hz); δC/ppm

(100 MHz; CDCl3) 146.3 (CH), 141.3 (CH), 141.1 (CH), 140.5 (CH), 119.8 (C), 116.2 (C), 116.1

(C), 68.7 (C); MS (70eV, EI): m/z (%): 517.9 ([M]+, 20), 488.9 (18), 390.9 (100), 264.0 (39), 150.0

(55); HRMS: calcd for C16H8I2O4 [M]+: 517.8512; found 517.8520.

Dibromohexafuran 22

O

O

I

O

O

I

O

O

O

OO

O

BrBr

O

B OO

Br2.2 equiv.



22X-ray

21

Diiodotetrafuran 21 (306 mg, 0.591 mmol), 11 (355 mg, 1.30 mmol, 2.2 mol equiv), silver

carbonate (717 mg, 2.60 mmol, 4.4 mol equiv) and tetrakis(triphenylphosphine)palladium (34 mg,



degassed THF (3 mL) was added and the stirred solution heated to reflux for 15 minutes. The


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reaction mixture was cooled then passed through a short plug of flash silica, washing with diethyl

ether. The solvent was removed from filtrate under reduced pressure and the residue was

recrystallised from chloroform/hexane to give the title compound as a white crystalline solid (168

mg, 51%) from which crystals suitable for single crystal X-ray diffraction were obtained. Mp 142–

143 °C (chloroform/hexane); νmax (KBr)/cm–1 3146, 1611, 1588, 1538 and 1497; δH/ppm (400

MHz; CDCl3) 7.45 (2H, d, J 2.0 Hz), 7.41 (2H, d, J 1.6 Hz), 7.29 (2H, d, J 1.6 Hz), 7.26 (2H, d, J

1.6 Hz), 7.15 (2H, d, J 1.6 Hz), 7.00 (2H, d, J 1.6 Hz); δC/ppm (100 MHz; CDCl3) 141.5 (CH),

141.3 (CH), 141.1 (CH), 141.0 (CH), 140.5 (CH), 140.4 (CH), 117.3 (C), 116.7 (C), 115.8 (C),

115.6 (C), 115.5 (C), 101.0 (C); UV-Vis (MeCN) λmax 196 nm (ε = 36000); MS (70eV, EI): m/z

(%): 557.8 ([M81Br81Br]+, 20), 555.8 ([M81Br79Br]+, 40), 553.8 ([M79Br79Br]+, 20), 526.9 (100), 476.9

(85), 474.9 (84), 226.1 (91), 113.1 (70); HRMS: calcd for C24H1281Br79BrO6 [M]+: 555.8980; found

555.8976.

Diiodohexafuran 23

O

O

O

OO

O

BrBr

O

O

O

OO

O

II

22

nBuLi 2.1 equiv.I2 2.2 equiv.

Et2O, -78 °C, 97%

23

To a solution of dibromohexafuran 22 (60 mg, 0.11 mmol) in diethyl ether (2 mL) at –78 °C was

slowly added a solution of n-butyllithium in hexanes (1.60 M, 0.142 mL, 0.228 mmol, 2.1 mol

equiv). The solution was stirred at –78 °C for 10 min then a solution of iodine (61 mg, 0.239 mmol,

2.2 mol equiv) in diethyl ether (1 mL) was added drop-wise. The end-point of the reaction can be

observed when a red/brown colour persists. The solution was stirred at –78 °C for a further 5 min

then quenched with saturated aqueous sodium thiosulfate solution. After allowing to warm to room

temperature, the solution was diluted with diethyl ether and washed with water then brine. The


pressure to give the title compound as a yellow solid (69 mg, 97%). Mp 144–145 °C (diethyl ether);

νmax (film)/cm–1 3146, 2919, 2850, 2265, 1611, 1589, 1539 and 1497; δH/ppm (400 MHz; CDCl3)

7.85 (2H, d, J 2.0 Hz), 7.41 (2H, d, J 2.0 Hz), 7.29 (2H, d, J 1.6 Hz), 7.27 (2H, d, J 1.6 Hz), 7.15

(2H, d, J 1.6 Hz), 7.00 (2H, d, J 2.0 Hz); δC/ppm (100 MHz; CDCl3) 141.5 (CH), 141.3 (CH), 141.1

(CH), 141.0 (CH), 140.5 (CH), 140.4 (CH), 117.3 (C), 116.7 (C), 115.8 (C), 115.6 (C), 115.5 (C),

101.0 (C); MS (70eV, EI): m/z (%): 648.9 ([M]+, 33), 620.9 (50), 523.0 (74), 477.0 (58), 226.1

(100), 112.9 (80) HRMS: calcd for C24H12I2O6 [M]+: 649.8723; found 649.8734.


S12

Hexafuran 24

O

O

O

OO

O

BrBr

22X-ray24

nBuLi 2.2 equiv.THF, -78 °C, MeOH quench, 98% O

O

O

OO

O

Dibromohexafuran 22 (8.0 mg, 0.014 mmol) was dissolved in THF (0.5 mL) and the resulting

solution was cooled to –78 °C. A solution of n-butyllithium (1.6 M in hexanes, 0.020 mL, 0.032

mmol, 2.2 mol equiv) was added drop-wise, the resulting solution was stirred at –78 °C for 1 h then

quenched with methanol and allowed to warm to RT. The solution was then diluted in diethyl ether

(5 mL) and washed with water (2 × 5 mL). The organic phase was dried over MgSO4 and solvent

was removed under reduced pressure to give the title compound as a yellow powder (5.6 mg, 98%).

An analytical sample was obtained by recrystallisation from dichloromethane/hexane, which gave

crystals suitable for single crystal X-ray diffraction. Mp 130–131 °C (dichloromethane/hexane);

νmax (KBr)/cm–1 3148, 3123, 2955, 2920, 2851, 1764, 1618, 1588 and 1494; δH/ppm (600 MHz;

CDCl3) 7.58 (2H, d, 1.5 Hz), 7.35 (2H, dd, 1.6 and 1.6 Hz), 7.30 (2H, d, 1.7 Hz), 7.28 (2H, d, 1.7

Hz), 7.21 (2H, d, 1.4 Hz), 7.15 (2H, s), 6.34 (2H, dd, 1.8 and 0.8 Hz); δC/ppm (150 MHz; CDCl3)

143.0 (CH), 141.9, (CH), 141.4 (CH), 140.5 (CH), 139.6 (CH), 138.9 (CH), 118.6 (C), 117.1 (C),

116.2 (C), 115.6 (C), 115.4 (C), 109.5 (CH); MS (70eV, EI): m/z (%): 398.1 ([M]+, 70), 369.1

(100), 226.1 (30); HRMS: calcd for C24H14O6 [M]+: 398.0790; found 398.0791.

Dibromooctafuran 9

O

O

O

OO

O

II

O

O

O

OO

OO

O

BrBrO

B OO

Br2.2 equiv.



X-ray923

Diiodohexafuran 23 (69 mg, 0.11 mmol), furan 11 (64 mg, 0.23 mmol, 2.2 mol equiv), silver

carbonate (129 mg, 0.467 mmol, 4.4 mol equiv) and tetrakis(triphenylphosphine)palladium (6 mg,



degassed THF (0.6 mL) was added and the stirred solution heated to reflux for 15 minutes. The


S13

reaction mixture was cooled then passed through a short plug of flash silica, washing with diethyl

ether. The solvent was removed from filtrate under reduced pressure and the residue was the residue

subjected to flash chromatography on silica gel eluting with 30% toluene in hexane to give the title

compound as white solid (35 mg, 48%). A sample was recrystallised from chloroform to give a

crystals suitable for single crystal X-ray diffraction. Mp 190–192 °C (chloroform); νmax (KBr)/cm–1

3150, 2963, 2918, 2850, 1709, 1618 and 1497; δH/ppm (800 MHz; CDCl3) 7.85 (2H, d, J 1.5 Hz),

7.42 (2H, d, J 1.6 Hz), 7.31 (2H, d, J 1.5 Hz), 7.24 (2H, d, J 1.5 Hz), 7.15 (2H, d, J 1.5 Hz), 7.12

(2H, d, J 1.5 Hz), 7.11 (2H, d, J 1.5 Hz), 7.02 (2H, d, J 1.6 Hz); δC/ppm (200 MHz; CDCl3) 141.6

(CH), 141.2 (CH), 141.1 (CH), 141.1 (CH), 141.1 (CH), 140.6 (CH), 140.6 (CH), 140.4 (CH),

117.4 (C), 116.8 (C), 116.7 (C), 115.9 (C), 115.7 (C), 115.7 (C), 115.5 (C), 101.1 (C); UV-Vis

(MeCN) λmax 195 nm (ε = 38000); MS (70eV, EI): m/z (%): 689.9 ([M81Br81Br]+, 18), 687.9

([M81Br79Br]+, 33), 685.9 ([M79Br79Br]+, 17), 658.9 (100), 609.0 (35), 607.0 (34), 368.3 (80), 236.2

(76); HRMS: calcd for C32H1681Br79BrO8 [M]+: 687.9191; found 687.9170.

3,3'-Bifuran 25

S1 25

O

Br nBuLi 1.0 equiv.CuCl2 1.5 equiv.

OTHF, -78 °C to RT

60%

O

3,3'-Bifuran 25 is a known compound.4 To a solution 3-bromofuran5 S1 (149 mg, 1.01 mmol) in

THF (10 mL) at –78 °C was slowly added n-butyllithium in hexanes (1.60 M, 1.6 mL, 1.0 mmol,

1.0 mol equiv) and the solution was stirred at –78 °C for 1 h. To the resulting solution was added

solid CuCl2 (203 mg, 1.51 mmol, 1.5 mol equiv). The reaction mixture was stirred at –78 °C for 30

min then allowed to warm to RT overnight. The contents of the reaction flask were then poured into

a rapidly stirred mixture of water (50 mL) and 30–40 petrol (50 mL). The resulting suspension was

filtered through celite and the organic phase was washed with water, dried over MgSO4 and the

solvent was evaporated under reduced pressure at 0 °C to give the title compound as a yellow solid

(81 mg, 0.06 mmol, 60%). A sample was recrystallised from petrol to give crystals suitable for

single crystal X-ray analysis. Mp 40–45 °C (petroleum spirits); νmax (KBr)/cm–1 2958, 2930, 1721,

1642, 1586, 1529 and 1493; 1H NMR (300 MHz; CDCl3) δH/ppm 7.58 (2H, dd, J 1.5 and 0.9 Hz)

7.44 (2H, dd, J 1.8 and 1.5 Hz) 6.52 (2H, dd, J 1.8 and 0.9 Hz); 13C NMR (75 MHz; CDCl3)

δC/ppm 143.4 (CH), 138.3 (CH), 117.5 (C), 109.0 (CH); MS (70eV, EI): m/z (%): 134.0 ([M]+, 39),

105.0 (25), 63 (100); HRMS: calcd for C8H6O2 [M]+: 134.0368; found 134.0367.


S14

3-Furylboronpinacol Ester S2

S1 S2

O

Bri) nBuLi 1.0 equiv.iPrO3B 1.5 equiv.Et2O -78°C to RT

O

B OO

ii) pinacol 1.1 equiv.MgSO4, CH2Cl260% over 2 steps

3-Bromofuran S1 (10.1 g, 68.7 mmol) was dissolved in dry Et2O (300 mL) and the resulting

solution was cooled to –78 °C. A solution of n-butyllithium in hexanes (1.48 M, 47 mL, 69 mmol,

1.0 mol equiv) was slowly added and the mixture stirred for 15 min to –78 °C. This solution was

then transferred drop-wise, via cannula, into a stirred solution of triisopropyl borate (20 mL, 16 g,

87 mmol, 1.5 mol equiv) in Et2O (20 mL) at −78 °C. The resulting solution was allowed to warm to

RT, quenched with water and partitioned between Et2O (100 mL) and 1 N HCl (100 mL). The

aqueous phase was extracted with Et2O (50 mL) and the combined organic phases washed with

water, brine, dried over MgSO4 and the solvent was evaporated under reduced pressure at ambient

temperature. The residue was dissolved in dry dichloromethane (400 mL) and to this was added

pinacol (8.93 g, 75.6 mmol, 1.1 mol equiv) and MgSO4 (3.4 g). The mixture was stirred at RT

overnight. After filtration and evaporation, the crude product was passed through a short plug of

flash silica eluting with hexane. The solvent was removed under reduced pressure at ambient

temperature to give the title compound as a white powder (7.95 g, 60%). Mp 56–58 °C (hexane);

νmax (KBr)/cm–1 2980, 2933, 1572 and 1505; δH/ppm (400 MHz; CDCl3) 7.78 (1H, d, J 0.8 Hz)

7.46 (1H, dd, J 1.6 and 1.6 Hz) 6.58 (1H, d, J 0.8 Hz) 1.32 (12H, s); δC/ppm (100 MHz; CDCl3)

151.2 (CH), 143.0 (CH), 113.1 (CH), 83.6 (C), 24.9 (CH3) (C–B signal absent); MS (70eV, EI): m/z

(%): 194.1 ([M]+, 100), 179.1 (55), 151.1 (72); HRMS: calcd for C10H15BO3 [M]+: 194.1114; found

194.1116.


S15

Trifuran 26

O

OO

O

II

O

Bpin

X-ray

15

S2

26

2.5 equiv.

Pd(PPh3) 9 mol%Ag2CO3 5.0 equiv.

THF, RT, 40%

3,4-Diiodofuran 15 (104 mg, 0.325 mmol) was dissolved in THF (5 mL) and to the resulting

solution was added tetrakis(triphenylphosphine)palladium (35.5 mg, 0.0307 mmol), silver carbonate

(453 mg, 1.64 mmol, 5.0 mol equiv) and 3-furylboronpinacol ester S2 (158 mg, 0.813 mmol, 2.5

mol equiv). The mixture was stirred at RT overnight and then passed through a short plug of silica

eluting with diethyl ether. The solvent was removed under reduced pressure and the residue was

subjected to flash chromatography on silica gel eluting with petroleum spirits to give the title

compound as a colourless oil (26 mg, 40%). A sample was crystallised from

dichloromethane/petroleum spirits at –20 °C to give crystals suitable for single crystal X-ray

diffraction analysis. Care was needed to prevent the crystals melting since the melting point is

below 20 °C. Samples were manipulated on a dish cooled using an isopropanol/CO2 bath and

quickly transferred to the X-ray camera. Rf = 0.29 (hexane); νmax (film)/cm–1 3148, 2961, 1580, and

1490; δH/ppm (300 MHz; CDCl3) 7.52 (2H, s) 7.45 (2H, m) 7.43 (2H, dd, J 1.5 and 0.9 Hz) 6.45

(2H, dd, J 1.8 and 0.9 Hz); δC (75 MHz; CDCl3) 143.0 (CH), 140.4 (CH), 139.4 (CH), 117.0 (C),

116.1 (C), 110.5 (CH); MS (70eV, EI): m/z (%): 200.1 ([M]+, 94), 171.1 (100); HRMS: calcd for

C12H8O3 [M]+: 200.0473; found 200.0471.

Cyclotrifuran 27

O

Br BrNi(COD)2 1.1 equiv.PPh3 1.1 equiv.COD

DMF, 70 °C, 24h, 89%O

O

O

X-ray

427

This compound was synthesised using the conditions reported by Bendikov and co-workers for the

S and Se analogues.6 The compound has been synthesised previously Stinger and Wege through a

five step sequence from 3,6-dibromoanthranilic acid in 2% overall yield.7 Triphenylphosphine (289

mg, 1.1 mmol, 1.1 mol equiv) was weighed into a Schlenk bottle. The vessel was evacuated (ca. 1


S16

mmHg) then placed under at atmosphere of argon for a total of 3 cycles. Dry DMF (2.2 mL) and

cyclooctadiene (0.13 mL) were injected into the flask and the resulting solution was freeze/thaw

degassed then sealed under argon. The flask was transferred to a glove box and Ni(COD)2 (303 mg,

1.1 mmol, 1.1 mol equiv) was added. After removal from the glove box, a freeze/thaw degassed

solution of 3,4-dibromofuran 4 (226 mg, 1.0 mmol, 1 mol equiv) in DMF (1.8 mL) was added. The

flask was sealed and stirred under Ar at 70 °C for 24 h. The reaction mixture was poured into ice

cold water and extracted with chloroform (3 × 30 mL). The extracts were washed with water and

brine and then dried over MgSO4 and the solvent was removed under reduced pressure. The residue

was subjected to flash chromatography on silica gel eluting with petroleum spirits to give the title

compound as a white powder (59 mg, 89%). A sample was recrystallised from chloroform/hexane

to give crystals suitable for single crystal X-ray diffraction analysis. Mp 187–189 °C

(chloroform/hexane), Lit.7 189–190 °C; Rf = 0.17 (petrol); νmax (KBr)/cm–1 3141, 2957, 2924, 2858,

1730, 1539, 1504, 1494, 1462 and 1419; δH/ppm (400 MHz; CDCl3) 7.80 (6H, s); δC/ppm (100

MHz; CDCl3) 136.6 (CH), 114.1 (C); UV-Vis (MeCN) λmax (a) 215 nm (ε = 20000), (b) 222 nm (ε =

22000); MS (70eV, EI): m/z (%): 198.0 ([M]+, 100), 169.0 (22), 45 (46); HRMS: calcd for C12H6O3

[M]+: 198.0317; found 198.0317.

Cyclotetrafuran 28

O

Br

Ni(COD)2 1.1 equiv.bpy 1.1 equiv.COD

DMF, 70 °C, 24h, 51%

O

O

O

OO

Br

X-ray28

6

This compound was synthesised using the conditions reported by Bendikov and co-workers for the

S and Se analogues.6 The compound has been synthesised previously in 14% yield by Iyoda and

coworkers one step from the same substrate.1 2,2'-Bipyridyl (172 mg, 1.1 mmol, 1.1 mol equiv) was

weighed into a Schlenk bottle. The vessel was evacuated (ca. 1 mmHg) then placed under at

atmosphere of argon for a total of 3 cycles. Dry DMF (2.2 mL) and cyclooctadiene (0.13 mL) were

added and the resulting solution was freeze/thaw degassed and sealed under argon. The flask was

transferred to a glove box and Ni(COD)2 (303 mg, 1.1 mmol, 1.1 mol equiv) was added. The flask

was removed from the glove box and a freeze/thaw degassed solution of 3,4-dibromobifuran 6 (292

mg, 1.0 mmol, 1 mol equiv) in DMF (1.8 mL) was added, the flask was sealed and stirred at 70 °C

under Ar for 24 h. The reaction mixture was poured into ice cold water and extracted with


S17

chloroform (3 × 30 mL). The extracts were washed with water and brine and then dried over

MgSO4 and the solvent was removed under reduced pressure. The residue was subjected to flash

chromatography on silica gel eluting with hexane to give the title compound as a white powder (67

mg, 51%). A sample was recrystallised from chloroform/hexane to give crystals suitable for single

crystal X-ray diffraction. Mp 175–177 °C (chloroform/hexane), Lit.1 188–189 °C; Rf = 0.13

(hexane); νmax (KBr)/cm–1 3136, 1622, 1563, 1528, 1514 and 1488; δH/ppm (400 MHz; CDCl3)

7.48 (8H, s); δC/ppm (100 MHz; CDCl3) 140.6 (CH), 117.1 (C); UV-Vis (MeCN) λmax 199 nm (ε =

12000); MS (70eV, EI): m/z (%): 264.0 ([M]+, 100), 235.0 (23), 150.0 (18); HRMS: calcd for

C16H8O4 [M]+: 264.0423; found 264.0421.


S18

1.3 Lithium/Halogen Exchange Selectivity Experiments

A series of experiments were performed to ascertain the lithium for halogen exchange selectivity of

the dibromo-β-oligofuran series and the results are summarised in Scheme S1. The reaction

conditions used were essentially the same as those employed for the preparation dibromo-bifuran 6

and dibromotetrafuran 8 (see above). Thus, a solution of n-butyllithium in hexanes (1.0 mol equiv)

was added to a solution of the dibromide in diethyl ether at –78 °C. After stirring for the standard

time, methanol was added and the sample was worked up and subjected to 1H NMR analysis. For

3,4-dibromofuran 4, high selectivity for the product of single Br/Li exchange was observed.

Dibromobifuran 6 displayed 90% selectivity for the product of single Br/Li exchange. Beyond this,

no selectivity was witnessed and a statistical distribution of products is observed.

O

O

BrBr

O

O

BrBr

O

O

Br

O

OnBuLi 1.0 equiv.

Et2O -78 °C, 30 min + +

MeOH quench89%

5:90:5

O

O

Br

O

Br

O

O

Br

O

Br

O

O

Br

O O

O

O

1:2:1

nBuLi 1.0 equiv.

Et2O -78 °C, 30 minMeOH quench91%

+ +

O

O

Br

O

O

O

Br

O

O

O

Br

O

O

O

O

1:2:1

nBuLi 1.0 equiv.


+ +

O O OOBrBr

O

Br

nBuLi 1.0 equiv.

Et2O -78 °C, 30 minMeOH quench98% by NMR

O

BrBr

0:1:04

6

16

8

6

S1

S3 25

16 26S4

8 S5 S6

Scheme S1: Summary of Results From Lithium/Halogen Exchange Selectivity Experiments.


S19

Treatment of 3,4-dibromofuran 4 with 1 mol equiv of n-BuLi

O

Br

nBuLi 1.0 equiv.

Et2O -78 °C, 30 minMeOH quench98% by NMR

O

BrBr4 S1

3,4-Dibromofuran 4 (159 mg, 0.704 mmol) was dissolved in diethyl ether (3 mL) and the resulting

solution was cooled to −78 °C. A solution of n-butyllithium in hexanes (1.6 M, 0.44 mL, 0.70

mmol, 1.0 mol equiv) was added drop-wise at this temperature. The solution was allowed to stir for

30 min at −78 °C after which time methanol (1 mL) was added. The solution was warmed to RT

and durene (94.5 mg, 0.704 mmol) was added. An aliquot of this solution was diluted in CDCl3 and

subjected to 1H NMR spectroscopic analysis, which showed clean conversion to 3-bromofuran in

98% yield, as measured against the internal standard. 3-Bromofuran S1 is commercially available

and spectroscopic data matched those obtained from a commercial sample: δH/ppm (400 MHz;

CDCl3) 7.44 (1H, dd, 1.6 and 0.8 Hz), 7.37 (1H, dd, 1.6 and 1.6 Hz), 6.45 (1H, dd, 1.6 and 0.8 Hz).

Treatment of dibromobifuran 6 with 1 mol equiv of n-BuLi

O

O

BrBr

O

O

BrBr

O

O

Br

O

OnBuLi 1.0 equiv.

Et2O -78 °C, 30 min + +

MeOH quench89%

5:90:56 6 S3 25

Dibromobifuran 6 (215 mg, 0.737 mmol) was dissolved in diethyl ether (5 mL) and the resulting



30 min at −78 °C after which time methanol was added. The solution was warmed to ambient

temperature, diluted with diethyl ether (10 mL) and washed with dilute aqueous hydrochloric acid.

The organic phase was dried over MgSO4 and the solvent was removed under reduced pressure to

give a 5:90:5 ratio of 2:S3:25 (as determined by 1H NMR analysis) as a colourless oil (140 mg,

89%). An analytical sample of bifuran S3 was obtained by flash chromatography on silica gel

eluting with petroleum spirits. Colourless oil. Rf = 0.55 (petroleum spirits) νmax (film)/cm–1 3151,

1766, 1633, 1574, 1537, 1524 and 1491; δH/ppm (300 MHz; CDCl3) 7.90 (1H, dd, 1.5 and 0.6 Hz),

7.53 (1H, d, 1.8 Hz), 7.49 (1H, d, 1.8 Hz), 7.47 (1H, dd, 1.8 and 1.2 Hz), 6.58 (1H, dd, 1.8 and 1.0

Hz); δC/ppm (100 MHz; CDCl3) 143.1 (CH), 142.3 (CH), 139.7 (CH), 139.3 (CH), 118.8 (C), 115.2


S20

(C), 109.5 (CH), 100.4 (C); MS (70eV, EI): m/z (%): 213.9 ([M81Br]+, 15), 211.9 ([M79Br]+, 15),

163.1 (40), 149.1 (55), 105.0 (100); HRMS: calcd for C8H5O279Br [M]+: 211.9473; found 211.9475.

Treatment of dibromotrifuran 16 with 1 mol equiv of n-BuLi

O

O

Br

O

Br

O

O

Br

O

Br

O

O

Br

O O

O

O

1:2:1

nBuLi 1.0 equiv.


+ +

16 16 26S4

Dibromotrifuran 16 (29 mg, 0.081 mmol) was dissolved in diethyl ether (0.8 mL) and the resultinfg


mmol, 1.0 mol equiv) was added drop-wise at this temperature. The mixture was allowed to stir for

1 h at −78 °C then quenched with methanol. The solution was warmed to ambient temperature,

diluted with diethyl ether (5 mL) and washed with dilute aqueous hydrochloric acid. The organic

phase was dried over MgSO4 and the solvent was removed in vacuo to give a 1:2:1 ratio of

16:S4:26 (as determined by 1H NMR analysis) as a colourless oil (140 mg, 89%). An analytical

sample of S4 was obtained by preparative HPLC (Altech preparative column eluting with hexane

12mL/min, Rt 26 min) as a yellow oil. νmax (film)/cm–1 3149, 2925, 1768, 1663, 1577 and 1491;

δH/ppm (800 MHz; CDCl3) 7.68 (1H, d, 1.8 Hz), 7.56 (1H, d, 1.5 Hz), 7.52 (1H, d, 1.8 Hz), 7.42

(1H, dd, 1.5 and 1.5 Hz), 7.35 (1H, s), 7.34 (1H, d, 0.8 Hz), 6.40 (1H, d, 0.8 Hz); δC/ppm (400

MHz; CDCl3) 143.2 (CH), 142.0, (CH), 141.8 (CH), 141.2 (CH), 140.1 (CH), 139.4 (CH), 117.7

(C), 117.7 (C), 116.1 (C), 114.2 (C), 110.3 (CH), 102.1 (C); MS (70eV, EI): m/z (%): 279.9

([M81Br]+, 10), 277.9 ([M79Br]+, 10), 251.0 (14), 239.0 (16), 215.0 (35), 199.1 (90), 124 (84), 39.0

(100); HRMS: calcd for C12H7O381Br [M]+: 279.9558; found 279.9558.

Treatment of dibromotetrafuran 8 with 1 mol equiv of n-BuLi

O

O

Br

O

O

O

Br

O

O

O

Br

O

O

O

O

1:2:1

nBuLi 1.0 eq


+ +

O O OOBrBr

8 8 S5 S6


S21

Dibromotetrafuran 8 (125 mg, 0.295 mmol) was dissolved in diethyl ether (3 mL) and the resulting



30 min at −78 °C after which time methanol was added. The solution was warmed to ambient

temperature, diluted with diethyl ether (10 mL) and washed with dilute aqueous hydrochloric acid.

The organic phase was dried over MgSO4 and the solvent was removed under reduced pressure to

give a 1:2:1 ratio of 8:S5:S6 (as determined by 1H NMR analysis) as a colourless oil (96 mg, 94%).

Analytical samples of S5 and S6 were obtained flash chromatography on silica gel eluting with

hexane. Tetrafuran S5 was obtained as a yellow oil. Rf = 0.12 (hexane); νmax (film)/cm–1 3150,

2922, 2852, 1572, 1531 and 1492; δH/ppm (300 MHz; CDCl3) 7.99 (1H, d, 1.7 Hz), 7.16 (1H, d, 1.7

Hz), 7.45 (1H, d, 1.8 Hz), 7.40 (1H, d, 1.8 Hz), 7.38 (1H, d, 1.8), 7.33 (1H, dd, 1.8 and 1.8 Hz),

7.19 (1H, dd, 1.7 and 1.2 Hz), 7.08 (1H, d, 1.8 Hz), 6.35 (1H, dd, 1.8 and 0.6 Hz); δC/ppm (75

MHz; CDCl3) 143.0 (CH), 142.0, (CH), 141.5 (CH), 141.4 (CH), 141.0 (CH), 140.3 (CH), 139.8

(CH), 138.8 (CH), 118.6 (C), 117.2 (C), 116.1 (C), 115.9 (C), 115.7 (C), 115.1 (C), 109.4 (CH),

100.8 (C); MS (70eV, EI): m/z (%): 346.0 ([M81Br]+, 17), 344.0 ([M79Br]+, 17), 315.0 (34), 265.1

(100), 237.1 (30), 209.1 (21), 181.1 (28), 152.1 (62); HRMS: calcd for C16H9O481Br [M]+: 345.9664;

found 345.9660.

Tetrafuran S6 was obtained as a yellow solid, mp 52–54 °C (hexane); Rf = 0.8 (hexane); νmax (KBr

disc)/cm–1 3144, 3122, 2955, 2919, 2850, 1618, 1585 and 1492; δH/ppm (600 MHz; acetone-d6)

7.84 (1H, d, 1.2 Hz), 7.48 (2H, d, 1.5 Hz), 7.32 (2H, dd, 1.2 and 1.2 Hz), 7.13 (2H, s), 6.42 (2H, d,

1.5 Hz); δC/ppm (125 MHz; acetone-d6) 114.0 (CH), 143.3 (CH), 141.1 (CH), 139.3 (CH), 198.8

(C), 117.4 (C), 116.0 (C), 110.1 (CH); MS (70eV, EI): m/z (%): 266.1 ([M]+, 80), 237.1 (100),

209.1 (22), 181.1 (42), 152.1 (55); HRMS: calcd for C16H10O4 [M]+: 266.0579; found 266.0586.


S22

2 References 1 (a) S. M. H. Kabir, M. Miura, S. Sasaki, G. Harada, Y. Kuwatani, M. Yoshida and M. Iyoda,

Heterocycles, 2000, 52, 761–774; (b) G. Harada, M. Yoshida and M. Iyoda, Chem. Lett.,

2000, 29, 160–161.

2 This procedure relates to: A. K. Miller, C. C. Hughes, J. J. Kennedy-Smith, S. N. Gradl and

D. Trauner, J. Am. Chem. Soc., 2006, 128, 17057–17062.

3 M. Gorzynski and D. Rewicki, Liebigs Ann. 1986, 4, 625–637.

4 For the first synthesis see: H. Wynberg and J. W. van Reijendam, Recl. Trav. Chim. Pays-

Bas, 1967, 86, 381–384.

5 J. Srogl, M. Janda and I. Stibor, Collect. Czech. Chem. Commun., 1970, 35, 3478–3480.

6 A. Patra, Y. H. Wijsboom, L. J. W. Shimon and M. Bendikov, Angew. Chem., Int. Ed.,

2007, 46, 8814–8818.

7 M. B. Stringer and D. Wege, Tetrahedron Lett., 1980, 21, 3831–3834.


S23

3 Anisotropic Displacement Ellipsoid Plots

Figure S1. Anisotropic displacement ellipsoid plot of 25 (CCDC 860342) with labeling of selected atoms.

Ellipsoids show 30% probability levels. Asterisks indicate atoms generated by crystallographic symmetry.

Hydrogen atoms are drawn as circles with small radii.








S24




Figure S5. Anisotropic displacement ellipsoid plot of 8 (CCDC 860335) with labelling of selected atoms.

Asterisks indicate atoms generated by crystallographic inversion symmetry. Ellipsoids show 30% probability

levels. Hydrogen atoms are drawn as circles with small radii.


S25


Ellipsoids show 30% probability levels. Hydrogen atoms are drawn as circles with small radii.




Asterisks indicate atoms generated by crystallographic inversion symmetry. Ellipsoids show 30% probability

levels. Hydrogen atoms are drawn as circles with small radii.


S26




Asterisks indicate atoms generated by a crystallographic twofold-rotation symmetry operation. Ellipsoids show

30% probability levels. Hydrogen atoms are drawn as circles with small radii.


Asterisks indicate atoms generated by crystallographic 2-fold rotation symmetry. Ellipsoids show 30%

probability levels. Hydrogen atoms are drawn as circles with small radii.


S27

Figure S12. Anisotropic displacement ellipsoid plots of molecules one, two and three of 28 (CCDC 860345) with

labelling of selected atoms. Asterisks indicate atoms generated by a crystallographic two-fold symmetry

operation. Ellipsoids show 30% probability levels. Hydrogen atoms are drawn as circles with small radii.

4 UV-Vis Spectra of Dibromo-oligofurans and Cyclic Oligofurans

Figure S13. UV-Vis spectra of the dibromo-oligofurans.

Whereas a general increase in extinction coefficient from the bifuran to the octafuran is witnessed, the

increase is not linear throughout the series. This non-linear increase in extinction coefficient with

increasing number of furan rings is presumably due to the presence of different conformations and

different conformational equilibria throughout the series.

O

O

Br

O

O

Br

O

O

BrBr

O

Br Br

O

O

O

OO

O

BrBr

O

O

O

OO

OO

O

BrBr

O

O

Br

O

Br

O

O

Br

O

O

O

Br

O

O

O

OO

OO

Br Br

9

6

16

8

18

22

20

4


S28

Figure S14. UV-Vis spectra of cyclotrifuran 27 and cyclotetrafuran 28.

28

O

OO

27O

O

O

O


S29

5 1H and 13C NMR Spectra

O

O

BrBr

400 MHz 1H NMRCDCl3

6


S30

O

O

BrBr

100 MHz 13C NMRCDCl3

6


S31

O

O

Br

O

O

Br

8

400 MHz 1H NMRCDCl3


S32


8

O

O

Br

O

O

Br


S33

11

300 MHz 1H NMRCDCl3

O

B OO

Br


S34

75 MHz 13C NMRCDCl3

11O

B OO

Br


S35

16

300 MHz 1H NMRCDCl3

O

O

Br

O

Br


S36

O

O

Br

O

Br

75 MHz 13C NMRCDCl3

11


S37

17

400 MHz 1H NMRCDCl3

O

O

I

O

I


S38

O

O

I

O

I


17


S39

O

O

Br

O

O

O

Br

18

300 MHz 1H NMRCDCl3


S40

75 MHz 13C NMRCDCl3

18O

O

Br

O

O

O

Br


S41

O

O

I

O

O

O

I

19

300 MHz 1H NMRCDCl3


S42

75 MHz 13C NMRCDCl3

19O

O

I

O

O

O

I


S43

20

400 MHz 1H NMRCDCl3

O

O

O

OO

OO

Br Br


S44

O

O

O

OO

OO

Br Br


20


S45

21

400 MHz 1H NMRCDCl3

O

O

I

O

O

I


S46


21O

O

I

O

O

I


S47

22

400 MHz 1H NMRCDCl3

O

O

O

OO

O

BrBr


S48

O

O

O

OO

O

BrBr


22


S49

23

400 MHz 1H NMRCDCl3

O

O

O

OO

O

II


S50

O

O

O

OO

O

II


23


S51

24

600 MHz 1H NMRCDCl3

O

O

O

OO

O


S52

O

O

O

OO

O


24


S53

O

O

O

OO

OO

O

BrBr

9

800 MHz 1H NMRCDCl3


S54


9O

O

O

OO

OO

O

BrBr


S55

25

300 MHz 1H NMRCDCl3

O

O


S56

75 MHz 13C NMRCDCl3

25O

O


S57

S2

400 MHz 1H NMRCDCl3

O

B OO


S58


S2O

B OO


S59

O

O

O26

400 MHz 1H NMRCDCl3


S60


26O

O

O


S61

27

400 MHz 1H NMRCDCl3

O

O

O


S62


27O

O

O


S63

28

400 MHz 1H NMRCDCl3

O

O

O

O


S64


28

O

O

O

O


S65

S3

300 MHz 1H NMRCDCl3

O

Br

O


S66

75 MHz 13C NMRCDCl3

S3O

Br

O


S67

S4

800 MHz 1H NMRCDCl3

O

Br

O

O


S68


S4O

Br

O

O


S69

S5

300 MHz 1H NMRCDCl3

O

Br

O

O

O


S70

75 MHz 13C NMRCDCl3

S5O

Br

O

O

O


S71

S6

600 MHz 1H NMRacetone-d6

O

O

O

O


S72

150 MHz 13C NMRacetone-d6

S6O

O

O

O


S73

6 Computational Data All calculations were carried out on isolated molecules in the gas phase using GAUSSIAN 09.1 Cartesian coordinates of fully B3LYP/6-31G(d) optimized geometries are listed below, along with calculated energies. 1 M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, G.

Scalmani, V. Barone, B. Mennucci, G. A. Petersson, H. Nakatsuji, M. Caricato, X. Li, H. P. Hratchian, A. F. Izmaylov, J. Bloino, G. Zheng, J. L. Sonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven, J. A. Montgomery, Jr., J. E. Peralta, F. Ogliaro, M. Bearpark, J. J. Heyd, E. Brothers, K. N. Kudin, V. N. Staroverov, R. Kobayashi, J. Normand, K. Raghavachari, A. Rendell, J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, N. Rega, J. M. Millam, M. Klene, J. E. Knox, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, R. L. Martin, K. Morokuma, V. G. Zakrzewski, G. A. Voth, P. Salvador, J. J. Dannenberg, S. Dapprich, A. D. Daniels, Ö. Farkas, J. B. Foresman, J. V. Ortiz, J. Cioslowski, D. J. Fox, Gaussian 09, Revision A.1: Gaussian, Inc., Wallingford CT, 2009.

6.1 The Acyclic Series of beta-Oligofurans

Systems from the bifuran to the hexafuran were investigated, both with and without bromine. Only the four lowest energy conformations of the pentafuran and hexafuran are included here. NON-BROMINATED ACYCLIC SYSTEMS The stability order was as follows: beta-bifuran 25 t>c (that is, transoid more stable then cisoid conformation) beta-trifuran 26 ct>cc conf 1>tt>cc conf 2 beta-tetrafuran SA1 tct>ctc>ctt>ttt beta-pentafuran SA2 ctct conf 1>tttc>ctct conf 2>tctt beta-hexafuran 24 tctct conf 1>cctct>tctct conf 2>ctctc The bifuran (25) structures beta-bifuran transoid conformation SCF Energy = -458.8522284 au; Energy (0K) = -458.7312734 au Enthalpy (298K) = -458.7227844 au; Gibbs energy (298K) = -458.7653124 au

16 C -2.89908 0.17255 -0.52657 C -1.65022 0.36783 -1.02170 C -0.72857 -0.01437 0.02233


S74

C -1.51851 -0.41093 1.06669 C 1.51851 0.41049 -1.06685 C 0.72857 0.01439 -0.02232 C 1.65022 -0.36737 1.02187 C 2.89908 -0.17231 0.52666 H -3.89073 0.31437 -0.92835 H -1.40152 0.73775 -2.00673 H -1.30494 -0.77942 2.05821 H 1.30495 0.77854 -2.05854 H 1.40151 -0.73684 2.00708 H 3.89073 -0.31390 0.92853 O -2.83990 -0.30356 0.74984 O 2.83990 0.30328 -0.74994 beta-bifuran cisoid conformation SCF Energy = -458.8515416 au; Energy (0K) = -458.7304956 au Enthalpy (298K) = -458.7220706 au; Gibbs energy (298K) = -458.7636856 au

16 C -2.87847 0.49397 -0.41621 C -1.61053 0.84893 -0.75026 C -0.73051 -0.00615 0.00903 C -1.55876 -0.81684 0.73617 C 1.57938 -0.38253 0.99907 C 0.73058 0.00184 -0.00280 C 1.58872 0.41958 -1.08503 C 2.86574 0.24669 -0.65537 H -3.85476 0.84578 -0.71278 H -1.31878 1.63284 -1.43532 H -1.38019 -1.63016 1.42288 H 1.42092 -0.73934 2.00532 H 1.27731 0.78003 -2.05561 H 3.83316 0.41058 -1.10492 O -2.86671 -0.52293 0.49217 O 2.87988 -0.24365 0.61692


S75

The trifuran (26) structures beta-trifuran ct conformation SCF Energy = -687.6819176 au; Energy (0K) = -687.5099786 au Enthalpy (298K) = -687.4977106 au; Gibbs energy (298K) = -687.5490716 au

23 C 3.51039 -0.05230 1.35380 C 3.02163 0.46324 0.19696 C 1.65778 0.00057 0.08236 C 1.44582 -0.76534 1.19706 C 1.10433 0.59241 -2.29785 C 0.73777 0.27372 -1.02030 C -0.71699 0.24398 -1.03432 C -1.07686 0.55073 -2.31486 C -2.75773 -0.82788 0.00693 C -1.64833 -0.03027 0.06393 C -1.63969 0.51242 1.40247 C -2.73370 0.00623 2.02913 H 4.46080 0.01992 1.86020 H 3.54492 1.11179 -0.49198 H 0.59938 -1.32794 1.55628 H 2.06346 0.70387 -2.78009 H -2.03614 0.68308 -2.79173 H -3.17232 -1.45638 -0.76654 H -0.91242 1.19559 1.81677 H -3.14783 0.12499 3.01878 O 2.56125 -0.80541 1.97932 O 0.01562 0.76338 -3.09736 O -3.43017 -0.81546 1.19134 beta-trifuran cc conformation 1 SCF Energy = -687.6816200 au; Energy (0K) = -687.5096880 au Enthalpy (298K) = -687.4974180 au; Gibbs energy (298K) = -687.5487010 au

23


S76

C 2.67276 0.14531 2.03582 C 1.55196 0.54350 1.37964 C 1.64287 -0.00413 0.04669 C 2.82167 -0.69792 0.02283 C 1.05406 0.38371 -2.37307 C 0.71022 0.16889 -1.06878 C -0.74357 0.17046 -1.04562 C -1.12835 0.37282 -2.34044 C -2.81637 0.64156 0.32653 C -1.64064 -0.01879 0.09608 C -1.51129 -0.95521 1.18755 C -2.60950 -0.78797 1.96939 H 3.04991 0.30764 3.03398 H 0.75397 1.15692 1.77204 H 3.30994 -1.29340 -0.73358 H 2.00536 0.50108 -2.86946 H -2.09500 0.41195 -2.81919 H -3.32490 1.44114 -0.19041 H -0.70448 -1.65640 1.34380 H -2.95650 -1.25619 2.87784 O 3.46178 -0.61475 1.22198 O -0.04980 0.50718 -3.15992 O -3.41965 0.18431 1.45861 beta-trifuran tt conformation SCF Energy = -687.6814689 au; Energy (0K) = -687.5095469 au Enthalpy (298K) = -687.4972679 au; Gibbs energy (298K) = -687.5487359 au

23 C 3.53975 -0.41709 1.22583 C 3.00056 -0.48598 -0.01857 C 1.66540 0.05639 0.07919 C 1.51911 0.41050 1.39308 C 1.07140 0.50583 -2.31594 C 0.71955 0.23131 -1.02485 C -0.73583 0.19112 -1.02159 C -1.10816 0.44915 -2.31033 C -1.49896 -0.93327 1.13970 C -1.66418 -0.08840 0.07576 C -2.99899 0.44410 0.22108 C -3.51932 -0.11352 1.34461 H 4.49208 -0.70513 1.64414 H 3.46889 -0.88954 -0.90561


S77

H 0.71549 0.86512 1.94986 H 2.02513 0.66008 -2.79724 H -2.06959 0.49508 -2.79879 H -0.68837 -1.56865 1.45865 H -3.47956 1.16436 -0.42646 H -4.46425 -0.01765 1.85726 O 2.64813 0.12728 2.10203 O -0.02471 0.64214 -3.11071 O -2.61614 -0.95748 1.91997 beta-trifuran cc conformation 2 SCF Energy = -687.6788395 au; Energy (0K) = -687.5069985 au Enthalpy (298K) = -687.4946345 au; Gibbs energy (298K) = -687.5469695 au

23 C 2.60357 -0.53187 2.04336 C 1.46865 -0.70548 1.31760 C 1.65067 0.03099 0.08926 C 2.89309 0.59723 0.19433 C 1.10784 0.39411 -2.34488 C 0.73997 0.15945 -1.04914 C -0.71488 0.13499 -1.06350 C -1.07367 0.36995 -2.35800 C -2.43900 0.85889 0.65104 C -1.65238 -0.08186 0.05106 C -1.97351 -1.32374 0.71410 C -2.91423 -1.02891 1.64992 H 2.93116 -0.88359 3.00970 H 0.60163 -1.27994 1.60728 H 3.45876 1.25626 -0.44665 H 2.06767 0.47465 -2.83221 H -2.03273 0.43774 -2.84879 H -2.54943 1.92308 0.50870 H -1.56168 -2.29861 0.49173 H -3.45787 -1.61661 2.37391 O 3.48730 0.26115 1.37168 O 0.01920 0.52987 -3.15145 O -3.21079 0.30206 1.62546


S78

The tetrafuran (SA1) structures beta-tetrafuran tct conformation SCF Energy = -916.5120422 au; Energy (0K) = -916.2894772 au Enthalpy (298K) = -916.2731452 au; Gibbs energy (298K) = -916.3375312 au

30 C 0.96546 -3.91454 0.40247 C 1.65066 -2.90783 1.00072 C 1.26273 -1.68822 0.32897 C 0.36536 -2.07863 -0.62874 C 2.69812 -0.01862 1.55146 C 1.74763 -0.34330 0.62295 C 1.37463 0.92117 0.00272 C 2.13944 1.87068 0.61343 C 0.75092 1.52374 -2.35951 C 0.41450 1.17998 -1.08353 C -1.04202 1.17198 -1.04920 C -1.43068 1.50712 -2.31711 C -1.93224 0.90194 0.07550 C -1.60142 0.62725 1.37550 C -3.37710 0.88005 0.04217 C -3.78957 0.59775 1.30353 H 0.92411 -4.98210 0.55554 H 2.34712 -3.00728 1.82171 H -0.20123 -1.54406 -1.37329 H 3.27922 -0.60452 2.24695 H 2.20414 2.94166 0.49448 H 1.70243 1.64616 -2.85446 H -2.39597 1.64191 -2.78049 H -0.66242 0.53031 1.89514 H -4.01254 1.05092 -0.81573 H -4.75952 0.47754 1.76134 O 0.17479 -3.42716 -0.59557 O 2.94795 1.32097 1.55776 O -0.35462 1.72463 -3.12440 O -2.71860 0.43986 2.13230


S79

beta-tetrafuran ctc conformation SCF Energy = -916.5118008 au; Energy (0K) = -916.2890888 au Enthalpy (298K) = -916.2728918 au; Gibbs energy (298K) = -916.3341518 au

30 C -2.17029 0.00703 -2.05112 C -1.79186 -0.33762 -0.78575 C -0.33644 -0.29691 -0.78898 C 0.01263 0.06335 -2.06070 C 0.38842 -1.58133 1.26456 C 0.58077 -0.62779 0.30399 C 1.90045 -0.07332 0.57021 C 2.36493 -0.74366 1.66477 C 3.94353 0.99959 -0.46571 C 2.61493 0.99032 -0.14078 C 2.10425 2.26199 -0.59699 C 3.15633 2.92450 -1.14417 C -2.70359 -0.65474 0.31676 C -3.83077 -1.42593 0.24227 C -2.65175 -0.19023 1.68337 C -3.74205 -0.70785 2.30668 H -3.13583 0.14892 -2.51234 H 0.96470 0.20793 -2.54600 H -0.42166 -2.26342 1.46795 H 3.26957 -0.65497 2.24691 H 4.73360 0.27309 -0.35097 H 1.08826 2.61862 -0.50922 H 3.26912 3.89469 -1.60351 H -4.27692 -2.00095 -0.55489 H -1.89960 0.45135 2.11897 H -4.12976 -0.63783 3.31155 O -1.08807 0.25192 -2.83892 O 1.46117 -1.66402 2.09829 O 4.29020 2.16837 -1.07309 O -4.47560 -1.46649 1.44134


S80

beta-tetrafuran ctt conformation SCF Energy = -916.5115153 au; Energy (0K) = -916.2888143 au Enthalpy (298K) = -916.2726073 au; Gibbs energy (298K) = -916.3340223 au

30 C 2.33751 -0.86680 1.62220 C 1.88227 -0.12265 0.57105 C 0.59812 -0.70886 0.21075 C 0.41345 -1.74353 1.08345 C 0.04282 0.00610 -2.15514 C -0.30972 -0.34142 -0.88140 C -1.76532 -0.34119 -0.86989 C -2.14108 0.01403 -2.13348 C -3.83710 -1.35747 0.16424 C -2.67516 -0.63945 0.23873 C -2.58161 -0.21107 1.61483 C -3.68514 -0.69354 2.24293 C 2.58004 1.02827 -0.00429 C 2.04770 2.14690 -0.58645 C 4.00919 1.23862 -0.02163 C 4.21685 2.44714 -0.60482 H 3.22035 -0.79985 2.23953 H -0.37588 -2.46948 1.19900 H 0.99625 0.12096 -2.64610 H -3.10419 0.18407 -2.59020 H -4.32038 -1.89315 -0.63870 H -1.79480 0.38493 2.05391 H -4.05417 -0.63054 3.25524 H 1.03776 2.46421 -0.79008 H 4.76637 0.55597 0.33856 H 5.10054 3.01899 -0.84353 O 1.45849 -1.85399 1.94713 O -1.05621 0.22671 -2.92727 O -4.46516 -1.39762 1.37189 O 3.02926 3.01657 -0.95727


S81

beta-tetrafuran ttt conformation SCF Energy = -916.5114752 au; Energy (0K) = -916.2888672 au Enthalpy (298K) = -916.2726022 au; Gibbs energy (298K) = -916.3347962 au

30 C 2.37595 -0.07007 1.86083 C 1.86874 -0.22358 0.60117 C 0.70085 0.64472 0.54795 C 0.62561 1.23139 1.77842 C 0.19194 1.27869 -1.84264 C -0.19551 0.90697 -0.58741 C -1.65137 0.89043 -0.61798 C -1.99007 1.25391 -1.89108 C -2.40414 -0.26033 1.53126 C -2.59735 0.54805 0.44339 C -3.97481 0.97483 0.53115 C -4.48965 0.39772 1.64690 C 2.41580 -1.10582 -0.42895 C 1.76667 -1.69649 -1.47968 C 3.77958 -1.57431 -0.51726 C 3.83883 -2.39516 -1.59699 H 3.21067 -0.51964 2.37650 H -0.05721 1.94956 2.20527 H 1.16008 1.43665 -2.29204 H -2.93716 1.35744 -2.39813 H -1.55791 -0.82008 1.89515 H -4.49011 1.64112 -0.14678 H -5.45787 0.42606 2.12295 H 0.74713 -1.66851 -1.82846 H 4.59905 -1.30698 0.13547 H 4.63116 -2.96312 -2.06015 O 1.63253 0.80838 2.58887 O -0.88320 1.49165 -2.64784 O -3.54409 -0.36059 2.27123 O 2.61799 -2.48172 -2.19780


S82

The pentafuran (SA2) structures beta-pentafuran ctct conformation SCF Energy = -1145.3417423 au; Energy (0K) = -1145.0684073 au Enthalpy (298K) = -1145.0481843 au; Gibbs energy (298K) = -1145.1200353 au

37 C 1.77255 1.69597 -1.97458 C 1.44299 1.32381 -0.70470 C -0.01234 1.29420 -0.66750 C -0.41219 1.65053 -1.92505 C -0.58778 1.27822 1.79189 C -0.87116 1.00899 0.48224 C -2.21529 0.45227 0.48484 C -2.60500 0.44135 1.79197 C -4.30535 0.28485 -0.93665 C -3.00858 -0.03683 -0.64722 C -2.61848 -0.99222 -1.65749 C -3.70208 -1.16824 -2.45747 C 2.38876 1.00851 0.37628 C 3.24293 1.88347 0.98047 C 2.61824 -0.27494 1.02218 C 3.58831 -0.04077 1.95518 C 1.98332 -1.55734 0.73076 C 1.39432 -1.95204 -0.43980 C 1.86530 -2.69257 1.61492 C 1.22012 -3.66183 0.91659 H 2.71956 1.83467 -2.47394 H -1.38227 1.78121 -2.37740 H 0.27099 1.70690 2.28321 H -3.49849 0.09010 2.28525 H -5.01328 0.96277 -0.48444 H -1.66221 -1.48911 -1.73735 H -3.89731 -1.77976 -3.32518 H 3.42198 2.93995 0.84903 H 4.10348 -0.67815 2.65754 H 1.24971 -1.46745 -1.39172 H 2.20096 -2.75266 2.64094 H 0.90030 -4.66491 1.15387


S83

O 0.65937 1.89735 -2.73054 O -1.62987 0.94025 2.59971 O -4.74372 -0.39450 -2.03321 O 3.97922 1.26507 1.94362 O 0.92437 -3.22766 -0.34221 beta-pentafuran tttc conformation SCF Energy = -1145.3413317 au; Energy (0K) = -1145.0678557 au Enthalpy (298K) = -1145.0477117 au; Gibbs energy (298K) = -1145.1190477 au

37 C 1.02294 0.35435 -1.81095 C 0.64920 0.00742 -0.54293 C -0.80846 0.01889 -0.55287 C -1.16147 0.36811 -1.82465 C -1.65200 -1.43661 1.32905 C -1.73244 -0.32843 0.53530 C -2.93719 0.36948 0.96357 C -3.45775 -0.39275 1.97115 C -2.86622 2.68849 -0.10045 C -3.50740 1.62613 0.47787 C -4.89458 2.02176 0.55819 C -4.97361 3.26977 0.02956 C 1.55046 -0.26182 0.58075 C 1.33750 0.05941 1.89244 C 2.87753 -0.85970 0.54131 C 3.32540 -0.84211 1.83068 C 3.61522 -1.39581 -0.60591 C 4.94299 -1.20820 -0.87545 C 3.13524 -2.26653 -1.65370 C 4.20245 -2.53282 -2.45092 H 1.98416 0.49234 -2.27967 H -2.11644 0.49284 -2.31080 H -0.94602 -2.25088 1.37829 H -4.31896 -0.27490 2.61090 H -1.83737 2.87903 -0.35933 H -5.71406 1.43075 0.94317 H -5.78593 3.96159 -0.13292 H 0.51586 0.52994 2.40846 H 4.22850 -1.20652 2.29617


S84

H 5.71525 -0.62535 -0.39676 H 2.12880 -2.64084 -1.77248 H 4.33820 -3.12880 -3.34049 O -0.06348 0.57668 -2.60037 O -2.68949 -1.49184 2.20665 O -3.74364 3.69339 -0.37859 O 2.40446 -0.28555 2.66349 O 5.31729 -1.89434 -1.99076 beta-pentafuran ctct conformation 2 SCF Energy = -1145.3412881 au; Energy (0K) = -1145.0679031 au Enthalpy (298K) = -1145.0476771 au; Gibbs energy (298K) = -1145.1199951 au

37 C 2.64963 -4.46696 0.03520 C 3.14567 -3.46739 0.80695 C 2.51059 -2.24766 0.36133 C 1.67605 -2.63115 -0.65553 C 3.52232 -0.58723 1.96573 C 2.72852 -0.90788 0.89913 C 2.17978 0.35901 0.43694 C 2.69983 1.30872 1.26440 C 1.66349 0.97898 -1.95342 C 1.27542 0.61402 -0.69870 C -0.18156 0.57517 -0.73276 C -0.51967 0.91582 -2.01377 C -1.09677 0.24714 0.36108 C -0.84412 -0.59483 1.40855 C -2.46589 0.70415 0.55577 C -2.89574 0.09482 1.69836 C -3.25974 1.63315 -0.25431 C -4.56199 1.46516 -0.63656 C -2.87903 2.92914 -0.76621 C -3.97206 3.42839 -1.39998 H 2.82135 -5.53167 -0.00635 H 3.87786 -3.57046 1.59570 H 0.99650 -2.09478 -1.29745


S85

H 4.13425 -1.17402 2.63349 H 2.58032 2.38047 1.31181 H 2.63292 1.13813 -2.40083 H -1.46531 1.02328 -2.52030 H 0.01292 -1.18816 1.68397 H -3.81905 0.15385 2.25433 H -5.26658 0.65737 -0.50942 H -1.91818 3.41040 -0.65470 H -4.17426 4.35050 -1.92327 O 1.75006 -3.97580 -0.86357 O 3.51567 0.75452 2.19982 O 0.58920 1.16539 -2.76538 O -1.92584 -0.69862 2.22764 O -5.01174 2.54722 -1.33104 beta-pentafuran tctt conformation SCF Energy = -1145.3410447 au; Energy (0K) = -1145.0677177 au Enthalpy (298K) = -1145.0474937 au; Gibbs energy (298K) = -1145.1193527 au

37 C 2.59677 -1.29438 1.27899 C 2.20990 -0.63333 0.14898 C 0.86219 -1.10745 -0.13451 C 0.57699 -2.00301 0.85745 C 0.35783 -0.49151 -2.54489 C -0.01443 -0.78005 -1.26169 C -1.47122 -0.77385 -1.27533 C -1.82742 -0.48345 -2.55942 C -3.26553 -2.08793 -0.08496 C -2.40049 -1.03611 -0.16598 C -2.60780 -0.26230 1.04863 C -3.57748 -0.93139 1.74075 C 3.02798 0.35190 -0.56248 C 2.63087 1.51808 -1.15783 C 4.46203 0.31291 -0.72929 C 4.80537 1.44071 -1.40373 C -1.96222 0.98354 1.45229 C -1.36050 1.91519 0.65056 C -1.85374 1.51128 2.79187 C -1.20239 2.69797 2.68859


S86

H 3.49262 -1.25348 1.87967 H -0.28487 -2.61795 1.06139 H 1.31744 -0.40295 -3.02843 H -2.78481 -0.35424 -3.04121 H -3.45978 -2.92613 -0.73701 H -4.08024 -0.73769 2.67594 H 1.67249 1.99833 -1.27322 H 5.12686 -0.47371 -0.40021 H 5.74137 1.84161 -1.76158 H -1.20743 1.98121 -0.41440 H -2.19996 1.04352 3.70307 H -0.88578 3.44007 3.40539 O 1.61823 -2.12890 1.72357 O -0.73065 -0.30667 -3.34428 O -3.98819 -2.04278 1.06692 O 3.69814 2.18886 -1.67521 O -0.89356 2.96204 1.38681 The hexafuran (24) structures beta-hexafuran tctct conformation 1 SCF Energy = -1374.1728384 au; Energy (0K) = -1373.8486944 au Enthalpy (298K) = -1373.8245574 au; Gibbs energy (298K) = -1373.9054274 au

44 C 5.46205 -1.84322 -0.99642 C 5.18485 -0.78489 -0.19353 C 3.88744 -0.28983 -0.59586 C 3.49519 -1.11027 -1.62087 C 3.67616 1.74357 0.87941 C 3.17264 0.84677 -0.02174 C 1.80513 1.27826 -0.26685 C 1.62220 2.38581 0.50727 C 0.47359 1.11484 -2.41052 C 0.78958 0.68564 -1.15538 C -0.12990 -0.40680 -0.87287 C -0.90653 -0.52614 -1.99017 C -0.24065 -1.19354 0.35606 C 0.78232 -1.66219 1.13090


S87

C -1.45975 -1.65912 1.00157 C -1.04959 -2.36451 2.09489 C -2.85567 -1.44328 0.59597 C -3.75287 -2.42759 0.30012 C -3.58488 -0.19128 0.44952 C -4.84915 -0.55350 0.07772 C -3.11378 1.17395 0.66584 C -2.01891 1.58854 1.37343 C -3.72757 2.38610 0.17382 C -2.96117 3.41603 0.61281 H 6.29625 -2.52403 -1.07068 H 5.81229 -0.39813 0.59743 H 2.61769 -1.14374 -2.24549 H 4.64059 1.85276 1.35138 H 0.76997 3.02853 0.67038 H 0.87098 1.89870 -3.03736 H -1.72154 -1.18269 -2.25121 H 1.85571 -1.59610 1.04764 H -1.58683 -2.87248 2.88142 H -3.66873 -3.50302 0.25768 H -5.74620 0.01129 -0.12532 H -1.25132 1.06744 1.92165 H -4.61271 2.46104 -0.44261 H -3.01346 4.48779 0.49730 O 4.44180 -2.05752 -1.87473 O 2.74755 2.68264 1.21131 O -0.55123 0.38915 -2.93405 O 0.30759 -2.37663 2.18915 O -4.96916 -1.90728 -0.01764 O -1.90995 2.94872 1.34809 beta-hexafuran cctct conformation SCF Energy = -1374.1726895 au; Energy (0K) = -1373.8482845 au Enthalpy (298K) = -1373.8243005 au; Gibbs energy (298K) = -1373.9036755 au

44 C 0.98191 -2.03170 2.25493 C 1.39196 -1.47265 1.08110


S88

C 0.20248 -1.41160 0.23768 C -0.80228 -1.94156 1.00056 C 1.13699 -0.61662 -1.97264 C 0.09887 -0.94063 -1.14213 C -1.10315 -0.76492 -1.94999 C -0.66534 -0.35790 -3.17581 C -3.31083 -1.93712 -2.21532 C -2.51818 -0.99999 -1.61830 C -3.38195 -0.30043 -0.67788 C -4.60920 -0.88779 -0.80973 C 2.78398 -1.09107 0.78653 C 3.81609 -1.97366 0.65712 C 3.37663 0.23036 0.62493 C 4.70738 0.00171 0.40763 C 2.73719 1.54027 0.69843 C 1.45097 1.83557 1.05991 C 3.35213 2.81584 0.40752 C 2.40037 3.76057 0.61156 C -3.04188 0.80449 0.21756 C -3.61810 1.08759 1.42669 C -2.05310 1.83652 0.01820 C -2.11838 2.64811 1.10626 H 1.50247 -2.26200 3.17213 H -1.84922 -2.11707 0.81666 H 2.20595 -0.59727 -1.83895 H -1.18649 -0.09497 -4.08391 H -3.11152 -2.69333 -2.95943 H -5.56916 -0.69051 -0.35718 H 3.86008 -3.05178 0.69014 H 5.55053 0.65640 0.24909 H 0.60569 1.23635 1.35459 H 4.36792 2.99109 0.08121 H 2.38605 4.83611 0.52292 H -4.37867 0.59697 2.01508 H -1.39373 1.94614 -0.82989 H -1.57375 3.52944 1.40705 O -0.34541 -2.32066 2.22635 O 0.68949 -0.26002 -3.20844 O -4.58247 -1.88638 -1.73582 O 4.99127 -1.33081 0.42475 O 1.23081 3.18123 1.01007 O -3.07163 2.20592 1.97705


S89

beta-hexafuran tctct conformation 2 SCF Energy = -1374.1722837 au; Energy (0K) = -1373.8480657 au Enthalpy (298K) = -1373.8239767 au; Gibbs energy (298K) = -1373.9044967 au

44 C 2.00593 -0.25815 -2.50966 C 1.88141 -0.64893 -1.20938 C 0.46256 -0.93138 -1.01724 C -0.11815 -0.67621 -2.22976 C 0.39648 -1.87541 1.32926 C -0.20526 -1.42820 0.18450 C -1.63557 -1.60546 0.41383 C -1.74438 -2.13958 1.66356 C -3.58944 -2.30843 -1.00187 C -2.77790 -1.34507 -0.47788 C -3.31517 -0.07839 -0.95572 C -4.39441 -0.41388 -1.72553 C 3.01016 -0.78535 -0.27388 C 4.02517 -1.68703 -0.40804 C 3.32549 -0.01627 0.92219 C 4.49876 -0.54206 1.38797 C -2.84767 1.27707 -0.68201 C -1.99296 1.69563 0.30230 C -3.21182 2.47549 -1.40218 C -2.55348 3.50073 -0.80400 C 2.58905 1.09392 1.51871 C 1.60507 1.85915 0.95230 C 2.76443 1.62723 2.84998 C 1.88253 2.65140 2.97513 H 2.85519 0.05818 -3.09618 H -1.13235 -0.74272 -2.58711 H 1.42643 -1.95279 1.63579 H -2.59682 -2.42643 2.26054 H -3.57662 -3.38593 -0.93700 H -5.11996 0.17094 -2.26992 H 4.21490 -2.46816 -1.12860 H 5.13387 -0.29627 2.22525 H -1.46155 1.18536 1.08882 H -3.86464 2.54533 -2.26131 H -2.50382 4.56320 -0.98721


S90

H 1.12933 1.85787 -0.01468 H 3.44842 1.27200 3.60836 H 1.64247 3.33547 3.77469 O 0.80437 -0.26630 -3.14401 O -0.52342 -2.30870 2.23531 O -4.57547 -1.76396 -1.76349 O 4.93775 -1.55684 0.59146 O -1.80351 3.04346 0.23823 O 1.16530 2.80723 1.82662 beta-hexafuran ctctc conformation SCF Energy = -1374.1722202 au; Energy (0K) = -1373.8480552 au Enthalpy (298K) = -1373.8239332 au; Gibbs energy (298K) = -1373.9044902 au

44 C -1.52724 -3.46738 -0.08559 C -0.80889 -2.40517 -0.54927 C -1.75935 -1.31005 -0.67263 C -2.95822 -1.82349 -0.26619 C -0.61934 0.35997 -2.18072 C -1.49619 0.03544 -1.18442 C -2.12453 1.28855 -0.79816 C -1.56210 2.24214 -1.59535 C -4.28545 2.24068 0.11864 C -3.12861 1.52314 0.24391 C -3.09092 1.09665 1.62308 C -4.21200 1.59326 2.20755 C 0.63235 -2.37552 -0.83544 C 1.28572 -3.07219 -1.80863 C 1.65250 -1.58300 -0.16536 C 2.82141 -1.88026 -0.80680 C 1.47159 -0.70433 0.99079 C 0.59948 -0.90301 2.02364 C 2.19130 0.51529 1.32080 C 1.67961 0.93163 2.51496 C 3.22917 1.20107 0.54515 C 4.42983 1.65965 1.01089 C 3.18908 1.58122 -0.84745


S91

C 4.35278 2.23516 -1.09883 H -1.25552 -4.47973 0.17278 H -3.94936 -1.40485 -0.19159 H 0.04900 -0.22851 -2.78895 H -1.68098 3.31352 -1.64917 H -4.75562 2.73839 -0.71590 H -2.30633 0.52549 2.09858 H -4.61296 1.54999 3.20872 H 0.95084 -3.76902 -2.56210 H 3.84000 -1.55496 -0.66597 H -0.11926 -1.67817 2.23683 H 1.87023 1.79774 3.13011 H 4.91667 1.60104 1.97254 H 2.37653 1.40768 -1.53850 H 4.76926 2.70605 -1.97620 O -2.83472 -3.13230 0.09314 O -0.64575 1.69665 -2.44273 O -4.95623 2.29477 1.30291 O 2.61621 -2.78322 -1.80675 O 0.71180 0.08186 2.95825 O 5.12562 2.29208 0.02536 BROMINATED ACYCLIC SYSTEMS The stability order was as follows: dibromo-beta-bifuran 6 t>c (that is, transoid more stable then cisoid conformation) dibromo-beta-trifuran 16 tt>ct>cc dibromo-beta-tetrafuran 8 tct conf 1> tct conf 2> ctc>ctt dibromo-beta-pentafuran 18 ctct>cttt>tctt>ccct dibromo-beta-hexafuran 22 ctcct>tccct>tcctt>ctctc The dibromobifuran (6) structures Dibromo-beta-bifuran transoid conformation SCF Energy = -5601.0549805 au; Energy (0K) = -5600.9532105 au Enthalpy (298K) = -5600.9421275 au; Gibbs energy (298K) = -5600.9924085 au

16 Br 3.09527 0.24456 -0.68973 Br -3.07265 -0.67819 0.46364


S92

C 2.20333 -0.69594 1.87486 C 1.85659 -0.18031 0.66762 C 0.41540 -0.05402 0.63986 C 0.02132 -0.51686 1.86813 C -0.05864 1.23267 -1.49491 C -0.43649 0.45884 -0.42880 C -1.86241 0.29186 -0.60946 C -2.21699 0.95778 -1.73834 H 3.14914 -0.95729 2.32138 H -0.94523 -0.62135 2.33125 H 0.89257 1.63118 -1.80472 H -3.15645 1.09703 -2.24851 O 1.08606 -0.90628 2.62010 O -1.11907 1.53922 -2.29008 Dibromo-beta-bifuran cisoid conformation SCF Energy = -5601.0521354 au; Energy (0K) = -5600.9506964 au Enthalpy (298K) = -5600.9395214 au; Gibbs energy (298K) = -5600.9896154 au

16 Br -1.13025 -1.46736 1.31624 Br 1.17100 1.45777 1.29103 C -2.90854 -0.35323 -0.67649 C -1.63528 -0.56311 -0.25159 C -0.75114 -0.00049 -1.24301 C -1.58669 0.50967 -2.19551 C 1.51725 -0.49333 -2.24770 C 0.71193 0.00971 -1.26583 C 1.62669 0.56513 -0.29842 C 2.88603 0.35853 -0.76443 H -3.87568 -0.60334 -0.27101 H -1.40422 1.04213 -3.11643 H 1.30604 -1.01903 -3.16636 H 3.86539 0.60576 -0.38754 O -2.89154 0.30500 -1.87014 O 2.83165 -0.29091 -1.96177


S93

The dibromotrifuran (16) structures Dibromo-beta-trifuran tt conformation SCF Energy = -5829.8839210 au; Energy (0K) = -5829.7315410 au Enthalpy (298K) = -5829.7164870 au; Gibbs energy (298K) = -5829.7766120 au

23 Br 3.86727 -0.96288 -1.38224 Br -3.82990 1.73452 0.34170 C -3.51127 -0.89410 1.48711 C -2.97707 0.10067 0.73179 C -1.66018 -0.32250 0.31216 C -1.52220 -1.56791 0.86301 C -1.03464 1.17847 -1.60933 C -0.70940 0.38902 -0.54304 C 0.74670 0.38163 -0.49625 C 1.14785 1.16022 -1.54452 C 1.42588 -0.42115 1.81923 C 1.63189 -0.26161 0.47550 C 2.94170 -0.83115 0.25328 C 3.40591 -1.28217 1.44765 H -4.45094 -1.00874 2.00305 H -0.73036 -2.29873 0.82640 H -1.97807 1.47422 -2.03891 H 2.11975 1.45250 -1.90791 H 0.61196 -0.14631 2.47073 H 4.31620 -1.77434 1.75005 O -2.62638 -1.92381 1.57665 O 0.07993 1.65125 -2.22678 O 2.48298 -1.03779 2.41710


S94

Dibromo-beta-trifuran ct conformation SCF Energy = -5829.8834689 au; Energy (0K) = -5829.7311539 au Enthalpy (298K) = -5829.7160659 au; Gibbs energy (298K) = -5829.7763689 au

23 Br 1.40074 -2.21997 0.11952 Br -3.47112 0.26301 -1.16612 C -2.73617 -0.28620 1.56227 C -2.35505 0.19744 0.35170 C -0.97419 0.61078 0.45633 C -0.64673 0.33618 1.75710 C -0.50043 1.89919 -1.67131 C -0.11011 1.19708 -0.56451 C 1.34509 1.20637 -0.59994 C 1.68306 1.91161 -1.71698 C 3.30789 1.24782 1.00032 C 2.30376 0.60505 0.33239 C 2.45208 -0.78013 0.71242 C 3.51138 -0.86082 1.55993 H -3.65892 -0.70070 1.93511 H 0.25921 0.46937 2.32566 H -1.46590 2.16558 -2.06844 H 2.63362 2.15602 -2.16610 H 3.60157 2.28519 1.05170 H 3.98497 -1.67940 2.07784 O -1.69542 -0.20635 2.43379 O 0.57651 2.33905 -2.37824 O 4.04706 0.37872 1.74407


S95

Dibromo-beta-trifuran cc conformation SCF Energy = -5829.8812893 au; Energy (0K) = -5829.7292053 au Enthalpy (298K) = -5829.7140283 au; Gibbs energy (298K) = -5829.7747083 au

23 Br 0.41099 0.12934 2.63226 Br -0.45950 -1.74246 -1.96614 C -2.71606 -1.50543 -0.17395 C -1.64610 -0.91206 -0.76527 C -1.62101 0.46478 -0.33700 C -2.69952 0.58041 0.49271 C -1.00420 2.73733 -1.23138 C -0.67721 1.52524 -0.69713 C 0.76966 1.53545 -0.56621 C 1.17024 2.75267 -1.03464 C 2.71443 -0.07632 -0.70111 C 1.64945 0.48246 -0.05414 C 1.61264 -0.19109 1.22051 C 2.63752 -1.08313 1.24204 H -3.12397 -2.50275 -0.21038 H -3.08162 1.40179 1.07909 H -1.94428 3.17622 -1.52917 H 2.13791 3.22444 -1.11275 H 3.12576 0.07176 -1.68771 H 2.99407 -1.78420 1.97944 O -3.37190 -0.59770 0.60150 O 0.10574 3.49538 -1.44268 O 3.32252 -1.02141 0.06630


S96

The dibromotetrafuran (8) structures Dibromo-beta-tetrafuran tct conformation 1 SCF Energy = -6058.7153235 au; Energy (0K) = -6058.5120335 au Enthalpy (298K) = -6058.4930575 au; Gibbs energy (298K) = -6058.5631245 au

30 Br -4.12706 -1.21789 0.38119 Br 4.04218 -1.31368 0.77221 C 2.09003 -2.55872 -0.93597 C 2.56041 -1.40736 -0.39041 C 1.71542 -0.32576 -0.84527 C 0.79350 -0.94440 -1.64763 C 2.91269 1.78941 -0.12716 C 1.80909 1.10220 -0.55354 C 0.76400 2.10770 -0.69952 C 1.34331 3.29238 -0.35269 C -1.14921 2.49583 -2.28447 C -0.62795 1.94958 -1.14902 C -1.73058 1.23926 -0.51325 C -2.80477 1.42894 -1.33915 C -1.70894 0.51916 0.75716 C -0.80278 0.66789 1.77362 C -2.62386 -0.48495 1.25257 C -2.20446 -0.85352 2.49063 H 2.39964 -3.58914 -0.86718 H -0.04024 -0.57405 -2.22121 H 3.91984 1.48775 0.10808 H 0.96218 4.30049 -0.29211 H -0.71438 3.08898 -3.07461 H -3.83273 1.11000 -1.29164 H 0.06446 1.29650 1.89207 H -2.57240 -1.56278 3.21444 O 1.00560 -2.28747 -1.70960 O 2.64529 3.11832 -0.00195 O -2.46729 2.18970 -2.41644 O -1.08744 -0.15289 2.82146


S97

Dibromo-beta-tetrafuran tct conformation 2 SCF Energy = -6058.7146797 au; Energy (0K) = -6058.5113517 au Enthalpy (298K) = -6058.4923347 au; Gibbs energy (298K) = -6058.5646667 au

30 Br 4.96930 -0.53926 -0.96612 Br -4.92644 -0.53123 1.16885 C -2.83831 0.91312 -1.10127 C -1.86485 0.71109 -0.15953 C -0.72325 1.49610 -0.61627 C -1.12527 2.09050 -1.77407 C 0.93447 2.67398 0.87191 C 0.59652 1.66884 0.01697 C 1.80185 0.86191 -0.13832 C 2.74294 1.46824 0.65037 C 0.97553 -1.08275 -1.53897 C 1.96840 -0.33273 -0.96301 C 3.18530 -1.00576 -1.36376 C 2.83702 -2.07388 -2.12661 C -1.95070 -0.10912 1.04666 C -0.91142 -0.51811 1.84206 C -3.11774 -0.68121 1.68318 C -2.69922 -1.36688 2.77808 H -3.84843 0.55403 -1.20418 H -0.62831 2.75602 -2.46345 H 0.37760 3.50472 1.27797 H 3.77615 1.25062 0.86249 H -0.09896 -1.00176 -1.53429 H 3.40711 -2.83724 -2.63127 H 0.15356 -0.36174 1.79242 H -3.21599 -1.93493 3.53484 O -2.40257 1.74697 -2.08452 O 2.22980 2.56715 1.26765 O 1.48418 -2.13219 -2.24110 O -1.34774 -1.27475 2.88616


S98

Dibromo-beta-tetrafuran ctc conformation SCF Energy = -6058.7142244 au; Energy (0K) = -6058.5112364 au Enthalpy (298K) = -6058.4922374 au; Gibbs energy (298K) = -6058.5609384 au

30 Br 1.43492 1.04955 1.81049 Br -1.69671 -0.97014 1.61782 C 1.73277 -2.47780 -1.05022 C 1.70752 -1.11983 -0.92122 C 0.37523 -0.70984 -1.33480 C -0.26849 -1.86610 -1.67265 C 0.52584 1.78788 -1.69701 C -0.16578 0.64622 -1.40768 C -1.54395 1.07018 -1.22058 C -1.54451 2.42065 -1.41447 C -3.90349 0.21774 -1.56969 C -2.72157 0.26451 -0.88525 C -2.93033 -0.60626 0.24793 C -4.19470 -1.09605 0.15936 C 2.82341 -0.29537 -0.44857 C 4.09566 -0.27598 -0.94715 C 2.86082 0.62742 0.66183 C 4.12567 1.11714 0.74365 H 2.48841 -3.21849 -0.83688 H -1.25970 -2.07299 -2.04364 H 1.56261 1.98090 -1.92240 H -2.32116 3.16774 -1.35276 H -4.23486 0.68400 -2.48505 H -4.77498 -1.76380 0.77579 H 4.56046 -0.78274 -1.77915 H 4.60801 1.81464 1.40956 O 0.54209 -2.94729 -1.50552 O -0.29687 2.87279 -1.70498 O -4.80448 -0.59672 -0.95277 O 4.89542 0.56926 -0.23887


S99

Dibromo-beta-tetrafuran ctt conformation SCF Energy = -6058.7140079 au; Energy (0K) = -6058.5110689 au Enthalpy (298K) = -6058.4919949 au; Gibbs energy (298K) = -6058.5618199 au

30 Br -2.13274 -1.05190 1.39292 Br 4.62576 -0.41957 0.35033 C 1.59800 -1.63261 -0.87194 C 1.19445 -0.41633 -0.39903 C 0.05985 -0.03458 -1.22502 C -0.11374 -1.06268 -2.10415 C -0.25214 2.48210 -1.22446 C -0.72768 1.20325 -1.18074 C -2.17433 1.33264 -1.13886 C -2.42861 2.67322 -1.16424 C -4.23932 0.05833 -1.88891 C -3.17236 0.26426 -1.06102 C -3.27740 -0.78419 -0.07531 C -4.37667 -1.52311 -0.37730 C 1.75683 0.30829 0.73878 C 1.07509 1.05280 1.66294 C 3.13213 0.38285 1.17214 C 3.17302 1.15351 2.29038 H 2.38734 -2.30692 -0.58103 H -0.81320 -1.22898 -2.90873 H 0.74394 2.89365 -1.27554 H -3.34122 3.24822 -1.12412 H -4.58290 0.56560 -2.77752 H -4.83990 -2.38378 0.07777 H 0.02653 1.26911 1.79089 H 3.97219 1.47936 2.93652 O 0.81178 -2.03956 -1.90425 O -1.27168 3.38526 -1.21553 O -4.97705 -1.01535 -1.49023 O 1.91558 1.57195 2.60109


S100

The dibromopentafuran (18) structures Dibromo-beta-pentafuran ctct conformation SCF Energy = -6287.5454432 au; Energy (0K) = -6287.2914242 au Enthalpy (298K) = -6287.2685232 au; Gibbs energy (298K) = -6287.3475712 au

37 Br 4.40476 -1.66211 0.60327 Br -2.43288 -1.64333 -1.08038 C -0.40636 2.83739 -2.05400 C 0.12566 2.27388 -0.93187 C -1.00969 1.78101 -0.16260 C -2.11171 2.09890 -0.90711 C 0.01020 1.18375 2.07334 C -0.99273 1.12928 1.14546 C -2.04586 0.34162 1.77022 C -1.57382 0.00375 3.00403 C -4.57933 0.26636 1.77942 C -3.36060 -0.03881 1.24254 C -3.67219 -0.84877 0.08873 C -5.02451 -0.96573 0.02268 C 1.56061 2.22734 -0.60679 C 2.33871 3.31157 -0.32826 C 2.45058 1.07573 -0.52891 C 3.67655 1.58833 -0.20417 C 2.11192 -0.32035 -0.78923 C 1.03105 -0.78271 -1.49034 C 2.81637 -1.52254 -0.40374 C 2.11835 -2.58433 -0.88305 H 0.04074 3.31435 -2.91304 H -3.16898 1.95613 -0.75357 H 0.97974 1.65430 2.08014 H -1.98665 -0.58860 3.80644 H -4.87179 0.85533 2.63535 H -5.69258 -1.47616 -0.65243 H 2.12128 4.36643 -0.25571 H 4.64188 1.13743 -0.04465 H 0.20665 -0.28437 -1.97126 H 2.26630 -3.65087 -0.82989


S101

O -1.76231 2.73888 -2.05745 O -0.32809 0.50488 3.20464 O -5.59407 -0.28534 1.05709 O 3.62409 2.94339 -0.08012 O 1.01891 -2.14279 -1.55175 Dibromo-beta-pentafuran cttt conformation SCF Energy = -6287.5440872 au; Energy (0K) = -6287.2902652 au Enthalpy (298K) = -6287.2672692 au; Gibbs energy (298K) = -6287.3472712 au

37 Br -5.53382 -1.31435 -1.42205 Br 2.83627 -1.68658 1.61648 C 2.27452 0.65109 -1.44443 C 1.38309 0.82348 -0.42532 C 0.24128 -0.01395 -0.75883 C 0.55849 -0.60533 -1.94750 C -0.94925 -0.59932 1.37368 C -0.95838 -0.24616 0.05595 C -2.36318 -0.19851 -0.32599 C -3.05727 -0.53054 0.80514 C -2.37522 0.96875 -2.58065 C -2.93395 0.16582 -1.62188 C -4.21580 -0.20107 -2.18223 C -4.32180 0.39024 -3.40046 C 1.55753 1.68461 0.74792 C 0.65599 2.57305 1.25968 C 2.73416 1.80257 1.59233 C 2.42918 2.75153 2.52439 C 3.99016 1.05514 1.50427 C 5.25633 1.56474 1.44298 C 4.18127 -0.37539 1.50830 C 5.51817 -0.61111 1.45275 H 3.25049 1.06512 -1.64495 H 0.04119 -1.31353 -2.57612 H -0.14605 -0.77681 2.07191 H -4.10927 -0.62278 1.01894 H -1.43663 1.49545 -2.63477 H -5.08810 0.38798 -4.15890 H -0.34834 2.84658 0.97608 H 2.97121 3.15323 3.36695 H 5.63532 2.57454 1.40239


S102

H 6.11261 -1.51058 1.44163 O 1.78756 -0.21031 -2.37841 O -2.21348 -0.77425 1.84327 O -3.19771 1.11104 -3.65737 O 1.17082 3.22961 2.33616 O 6.19032 0.57340 1.41274 Dibromo-beta-pentafuran tctt conformation SCF Energy = -6287.5439832 au; Energy (0K) = -6287.2901452 au Enthalpy (298K) = -6287.2671652 au; Gibbs energy (298K) = -6287.3473322 au

37 Br -4.11122 -2.18323 0.58282 Br 4.89298 -1.61611 -1.23077 C 1.44765 -1.41121 -1.55306 C 1.66506 -0.34445 -0.72823 C 0.62728 0.62244 -1.05955 C -0.11197 0.03435 -2.04610 C 1.37066 2.87382 -0.15135 C 0.41584 1.97238 -0.53042 C -0.85300 2.67153 -0.37715 C -0.53573 3.91797 0.07729 C -3.05130 2.66747 -1.61452 C -2.20866 2.17773 -0.66081 C -2.93453 1.09240 -0.01752 C -4.14260 1.03497 -0.65487 C 2.71064 -0.25866 0.29216 C 2.61437 0.27547 1.54804 C 4.06589 -0.75666 0.22748 C 4.66521 -0.48431 1.41590 C -2.48764 0.27476 1.10641 C -1.58732 0.63032 2.07421 C -2.88937 -1.06218 1.47786 C -2.21047 -1.40099 2.60462 H 1.94936 -2.35837 -1.66938 H -0.96733 0.36306 -2.61421 H 2.44753 2.83111 -0.11355 H -1.13650 4.77298 0.34834 H -2.94942 3.45473 -2.34602


S103

H -5.00895 0.40634 -0.52940 H 1.80205 0.74229 2.08130 H 5.65463 -0.66335 1.80501 H -1.02866 1.53508 2.25113 H -2.18907 -2.28843 3.21640 O 0.37315 -1.19814 -2.35627 O 0.80953 4.05815 0.22250 O -4.22890 1.98547 -1.62500 O 3.78393 0.15146 2.23538 O -1.40712 -0.36964 2.98166 Dibromo-beta-pentafuran ccct conformation SCF Energy = -6287.5438826 au; Energy (0K) = -6287.2900406 au Enthalpy (298K) = -6287.2671146 au; Gibbs energy (298K) = -6287.3452976 au

37 Br -3.71556 0.96022 -1.11364 Br 2.50465 -2.88841 1.15711 C -1.34107 -0.32095 2.52854 C -1.26725 0.02718 1.21124 C -0.72540 1.37471 1.19275 C -0.52663 1.70254 2.50335 C -0.81973 3.55178 -0.05271 C -0.43208 2.24710 0.05131 C 0.32029 1.96915 -1.16386 C 0.31145 3.13784 -1.87069 C 0.72146 0.14762 -2.84392 C 0.93852 0.71972 -1.62434 C 1.87611 -0.16057 -0.94616 C 2.12545 -1.17746 -1.82459 C -1.66702 -0.82719 0.09054 C -1.18746 -2.07450 -0.19045 C -2.65533 -0.58309 -0.92937 C -2.69866 -1.68143 -1.72859 C 2.45618 -0.00492 0.38494 C 2.82057 1.15694 1.00632 C 2.77199 -1.03133 1.34989


S104

C 3.28378 -0.42408 2.45181 H -1.69765 -1.20776 3.02994 H -0.11432 2.57660 2.98402 H -1.42070 4.18580 0.58119 H 0.75297 3.42283 -2.81365 H 0.08082 0.41396 -3.67051 H 2.74793 -2.05615 -1.76991 H -0.38817 -2.65440 0.24539 H -3.28653 -1.94745 -2.59238 H 2.78395 2.19007 0.69929 H 3.64292 -0.78932 3.40041 O -0.89564 0.68422 3.32815 O -0.37652 4.10921 -1.21213 O 1.43475 -1.00286 -2.98238 O -1.79947 -2.60484 -1.28531 O 3.31814 0.92158 2.25276 The dibromohexafuran (22) structures Dibromo-beta-hexafuran ctcct conformation SCF Energy = -6516.3773394 au; Energy (0K) = -6516.0725724 au Enthalpy (298K) = -6516.0458214 au; Gibbs energy (298K) = -6516.1322554 au

44 C -0.547880 1.448924 2.753917 C -0.181585 1.975739 1.550846 C 1.150853 1.455651 1.283091 C 1.450901 0.665344 2.356823 O 0.429929 0.649960 3.256743 H -1.450328 1.525059 3.341073 H 2.318351 0.081893 2.620516 C 1.985868 2.884953 -0.623557 C 2.015819 1.753942 0.143334 C 3.112969 0.960805 -0.390409 C 3.626344 1.687794 -1.424356 O 2.954656 2.858488 -1.582004


S105

H 1.368960 3.768729 -0.602001 H 4.421795 1.494223 -2.127883 C 4.930946 -0.604988 0.393848 C 3.634620 -0.335760 0.053626 C 2.957872 -1.605491 0.182704 C 3.883479 -2.517950 0.580439 O 5.100253 -1.917629 0.712723 H 5.809043 0.018602 0.466183 H 3.836570 -3.574206 0.792298 C -0.999102 2.882980 0.732514 C -1.419563 4.130273 1.092881 C -1.536002 2.663729 -0.603265 O -2.163860 4.704340 0.106381 H -1.259456 4.729435 1.976583 C -2.222255 3.801840 -0.912288 H -2.795160 4.098472 -1.777974 C -1.385217 1.481604 -1.464316 C -0.708662 1.442509 -2.646645 C -1.894313 0.134430 -1.259433 O -0.748095 0.198463 -3.192727 H -0.142096 2.183711 -3.188997 C -1.465440 -0.582775 -2.342777 H -1.595555 -1.609652 -2.640873 C -2.727765 -0.343948 -0.160697 C -3.523869 0.404987 0.663837 C -2.926018 -1.697553 0.303970 O -4.169976 -0.372221 1.578581 H -3.731786 1.461215 0.714048 C -3.794782 -1.658692 1.346974 H -4.212561 -2.416633 1.989911 Br -2.123852 -3.267776 -0.361670 Br 1.144014 -1.969428 -0.160239 Dibromo-beta-hexafuran tccct conformation SCF Energy = -6516.3770480 au; Energy (0K) = -6516.0722510 au Enthalpy (298K) = -6516.0454860 au; Gibbs energy (298K) = -6516.1321960 au

44


S106

C -1.044393 1.601724 -2.727731 C -0.320173 1.070983 -1.699159 C -0.318542 2.090757 -0.660287 C -1.045897 3.128384 -1.170750 O -1.492962 2.850377 -2.425629 H -1.302289 1.226197 -3.706352 H -1.346147 4.080441 -0.759987 C 1.046301 3.128070 1.171429 C 0.318849 2.090608 0.660771 C 0.320291 1.070683 1.699496 C 1.044564 1.601163 2.728165 O 1.493294 2.849810 2.426276 H 1.346661 4.080165 0.760834 H 1.302377 1.225453 3.706738 C 0.433753 -1.429037 1.897250 C -0.265831 -0.275550 1.697536 C -1.644889 -0.684605 1.492291 C -1.638954 -2.048081 1.588034 O -0.385233 -2.514151 1.833279 H 1.490139 -1.627958 1.995593 H -2.415555 -2.792044 1.511141 C 0.265764 -0.275328 -1.697429 C -0.433967 -1.428702 -1.897257 C 1.644811 -0.684566 -1.492449 O 0.384874 -2.513934 -1.833349 H -1.490384 -1.627481 -1.995530 C 1.638666 -2.048043 -1.588130 H 2.415168 -2.792116 -1.511298 C -2.801789 0.168314 1.235531 C -3.041235 1.420793 1.729670 C -3.946531 -0.100889 0.397567 O -4.218398 1.925184 1.263524 H -2.485974 2.058616 2.398809 C -4.764149 0.982598 0.448074 H -5.707922 1.221189 -0.015287 C 2.801860 0.168200 -1.235842 C 3.041504 1.420572 -1.730150 C 3.946556 -0.101074 -0.397842 O 4.218754 1.924833 -1.264083 H 2.486339 2.058398 -2.399365 C 4.764361 0.982264 -0.448516 H 5.708170 1.220767 0.014817 Br 4.262389 -1.651532 0.628277 Br -4.262641 -1.651440 -0.628331


S107

Dibromo-beta-hexafuran tcctt conformation SCF Energy = -6516.3767165 au; Energy (0K) = -6516.0720315 au Enthalpy (298K) = -6516.0451665 au; Gibbs energy (298K) = -6516.1332985 au

44 C -3.903997 2.188304 0.320444 C -3.949118 0.841978 0.146275 C -2.588604 0.361415 0.064486 C -1.827754 1.491617 0.194223 O -2.607098 2.598650 0.352441 H -4.662057 2.945943 0.437393 H -0.765616 1.675542 0.164857 C -2.707467 -1.915067 -1.001301 C -2.132985 -1.013185 -0.151509 C -0.994260 -1.703451 0.437633 C -0.998550 -2.949753 -0.120346 O -2.030169 -3.093588 -0.997248 H -3.563925 -1.860823 -1.654189 H -0.368325 -3.814216 0.015844 C -0.331550 -0.431554 2.528734 C -0.053366 -1.231359 1.456071 C 1.350914 -1.586068 1.595846 C 1.776035 -0.967631 2.734890 O 0.768748 -0.260844 3.312991 H -1.232010 0.055494 2.867524 H 2.737679 -0.911697 3.221811 C 2.176890 -2.426398 0.718467 C 2.834986 -3.565377 1.082073 C 2.483238 -2.235091 -0.691900 O 3.519222 -4.096644 0.030444 H 2.893950 -4.111163 2.011665 C 3.294390 -3.277588 -1.034295 H 3.785053 -3.551152 -1.956224 C 2.024014 -1.162296 -1.583404 C 1.282774 -1.324962 -2.715933 C 2.226824 0.271644 -1.452030 O 1.004430 -0.126001 -3.295338 H 0.861312 -2.195122 -3.195342 C 1.578775 0.830934 -2.518476


S108

H 1.451503 1.849402 -2.847685 C 3.001583 0.969227 -0.429637 C 4.096709 0.502500 0.244598 C 2.804740 2.296677 0.102189 O 4.565650 1.422928 1.133522 H 4.639976 -0.427604 0.198265 C 3.765113 2.518930 1.036534 H 3.993391 3.353039 1.680303 Br 1.446558 3.514406 -0.368481 Br -5.526364 -0.184816 0.053609 Dibromo-beta-hexafuran ctctc conformation SCF Energy = -6516.3755052 au; Energy (0K) = -6516.0708332 au Enthalpy (298K) = -6516.0440072 au; Gibbs energy (298K) = -6516.1315192 au

44 C 1.454720 3.559427 0.797568 C 0.732437 2.655351 0.076358 C 1.708202 1.733718 -0.489350 C 2.922357 2.178264 -0.045732 O 2.785433 3.284579 0.737426 H 1.169992 4.412166 1.395258 H 3.933080 1.838385 -0.204101 C 0.363711 0.438463 -2.188566 C 1.454011 0.605476 -1.382546 C 2.311088 -0.538253 -1.658088 C 1.652142 -1.279111 -2.593736 O 0.467253 -0.702618 -2.926843 H -0.534068 1.014281 -2.337920 H 1.881718 -2.215889 -3.078228 C 4.797318 -1.033577 -1.748341 C 3.616236 -0.875931 -1.080111 C 3.943506 -1.161268 0.296731 C 5.267624 -1.461988 0.349004 O 5.804480 -1.387779 -0.901892 H 5.068419 -0.920065 -2.786926 H 5.933450 -1.742005 1.149564 C -0.732341 2.655362 -0.076893 C -1.454617 3.559349 -0.798216


S109

C -1.708129 1.733872 0.489021 O -2.785342 3.284591 -0.737941 H -1.169885 4.411992 -1.396041 C -2.922282 2.178403 0.045391 H -3.933017 1.838615 0.203872 C -1.453914 0.605780 1.382400 C -0.363602 0.438946 2.188443 C -2.310967 -0.537921 1.658162 O -0.467138 -0.701970 2.926971 H 0.534142 1.014847 2.337704 C -1.652020 -1.278554 2.593987 H -1.881570 -2.215241 3.078668 C -3.616135 -0.875703 1.080303 C -4.797156 -1.033259 1.748665 C -3.943545 -1.161228 -0.296473 O -5.804410 -1.387547 0.902362 H -5.068162 -0.919588 2.787258 C -5.267674 -1.461931 -0.348570 H -5.933573 -1.742068 -1.149029 Br -2.742521 -1.168067 -1.741779 Br 2.742276 -1.167693 1.741859

6.2 The Cyclic Series

The effect of successive replacement of the furan oxygens in cyclotrifuran 27 with methylene groups was examined. In all cases, closely related planar conformations were found. Lowest energy conformation of cyclotrimer 27:

21 C 0.72589 1.25839 0.00000 C -0.72589 1.25839 0.00000 C 1.67627 2.23761 0.00000 C -1.67627 2.23761 0.00000 C 2.77596 0.33289 0.00000 C -2.77596 0.33289 0.00000 C 1.45274 -0.00055 0.00000 C -1.45274 -0.00055 0.00000 C 0.72685 -1.25784 0.00000 C -0.72685 -1.25784 0.00000 C 1.09969 -2.57049 0.00000 C -1.09969 -2.57049 0.00000 H 1.64069 3.31606 0.00000


S110

H -1.64069 3.31606 0.00000 H 3.69214 -0.23715 0.00000 H -3.69214 -0.23715 0.00000 H 2.05144 -3.07891 0.00000 H -2.05144 -3.07891 0.00000 O 2.92475 1.68860 0.00000 O -2.92475 1.68860 0.00000 O 0.00000 -3.37720 0.00000 Lowest energy conformation of cyclotetramer 28:

28 C 0.74272 -0.85818 1.43201 C 1.64080 0.10725 0.79670 C 1.12738 -1.90738 2.21677 C 2.72457 0.69389 1.38490 C -1.05497 -1.94626 2.21856 C 2.71003 1.42388 -0.67206 C -0.70912 -0.88406 1.43318 C 1.63103 0.59303 -0.57167 C -1.64205 0.04918 0.80000 C 0.72016 0.24087 -1.66186 C -2.74467 0.59701 1.39057 C 1.08968 -0.07635 -2.93760 C -2.75932 1.32880 -0.66577 C -1.09272 -0.11358 -2.93537 C -1.65184 0.53593 -0.56802 C -0.73169 0.21598 -1.66034 H 3.12476 0.65405 2.38665 H 2.09473 -2.29801 2.49404 H -2.00731 -2.37107 2.49736 H 3.09744 2.02621 -1.47968 H -3.14144 0.54243 2.39292 H 2.05143 -0.20077 -3.41162 H -3.16895 1.91790 -1.47223 H -2.05065 -0.27073 -3.40745 O 0.04824 -2.57775 2.70528 O 3.38745 1.49482 0.50637 O -3.43667 1.37504 0.51397 O 0.00100 -0.29212 -3.72563


S111

Lowest energy conformation of mono-cyclopentadienyl system SC1:

23 C -1.45016 -0.02111 -0.02401 C -0.74462 -0.39641 1.19334 C -2.77333 0.05712 -0.35076 C -1.18059 -0.79454 2.41120 C -1.67477 0.65690 -2.15804 C 1.18280 -0.75167 2.42383 C -0.72631 0.37559 -1.21953 C 0.74571 -0.36938 1.20130 C 0.72519 0.40192 -1.21177 C 1.45014 0.03151 -0.00851 C 1.67280 0.71763 -2.14015 C 2.77302 0.15774 -0.32112 C 0.00151 -1.05665 3.30418 H -3.68853 -0.13346 0.18838 H -2.21092 -0.91562 2.72584 H -1.63985 0.98605 -3.18510 H 2.21343 -0.83535 2.74948 H 1.63694 1.04549 -3.16759 H 3.68872 0.00037 0.22780 H 0.01838 -2.09509 3.67264 H -0.01478 -0.42471 4.20683 O -2.92480 0.46697 -1.64174 O 2.92331 0.57307 -1.61049 Lowest energy conformation of bis-cyclopentadienyl system SC2:

25


S112

C -0.73843 -0.35297 1.21485 C -1.47753 -0.03102 0.00356 C -1.12351 -0.71118 2.47438 C -2.80260 0.01707 -0.26610 C 1.07401 -0.67538 2.50619 C -1.60238 0.58491 -2.21959 C 0.71407 -0.32930 1.23588 C -0.71829 0.32676 -1.22707 C 1.47703 0.01713 0.04632 C 0.74247 0.35057 -1.20592 C 2.80708 0.10848 -0.18489 C 1.64603 0.63784 -2.17257 C -3.00489 0.41290 -1.70374 C 3.03789 0.51137 -1.61627 H -2.08092 -0.86262 2.94880 H -3.61465 -0.19071 0.42147 H 2.02172 -0.79577 3.00819 H -1.36693 0.87298 -3.23788 H 3.60523 -0.07306 0.52598 H 1.43089 0.91857 -3.19738 H -3.59602 1.33804 -1.79987 H -3.56169 -0.35134 -2.26984 H 3.63543 -0.23406 -2.16566 H 3.60110 1.45532 -1.69569 O -0.03249 -0.91006 3.26897 Lowest energy conformation of tris-cyclopentadienyl system SC3:

27 C -0.71599 0.29690 -1.25447 C 0.74341 0.33162 -1.22957 C -1.59708 0.52544 -2.25680 C 1.64630 0.60260 -2.20147 C -2.79870 -0.00404 -0.29524 C 2.80417 0.12926 -0.19967 C -1.47405 -0.03713 -0.01699 C 1.47387 0.03300 0.03329 C -0.75788 -0.32990 1.22117 C 0.73064 -0.29449 1.24656


S113

C -1.20708 -0.65470 2.45646 C 1.15241 -0.59856 2.49671 C 3.03758 0.49952 -1.63885 C -0.03732 -0.85539 3.38070 C -3.00026 0.35587 -1.74185 H -1.35989 0.79090 -3.28089 H 1.43180 0.85732 -3.23327 H -3.61149 -0.20123 0.39468 H 3.60142 -0.02963 0.51772 H -2.24152 -0.76127 2.76317 H 2.17969 -0.65609 2.83859 H 3.59502 1.44487 -1.73775 H 3.64278 -0.25465 -2.16723 H -0.02058 -1.86885 3.81294 H -0.06834 -0.16933 4.24243 H -3.55056 -0.42578 -2.28994 H -3.59832 1.27374 -1.86045


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