supplementary materials for...osit bume 2 meo me o h bu3sn oh oh sime3 meo me o h ohco oh bu3sn meo...

www.sciencemag.org/content/354/6314/865/suppl/DC1

Supplementary Materials for

Asymmetric synthesis of batrachotoxin: Enantiomeric toxins show functional divergence against NaV

Matthew M. Logan, Tatsuya Toma, Rhiannon Thomas-Tran, J. Du Bois*

*Corresponding author. Email: [email protected]

Published18 November 2016, Science 354, 865 (2016) DOI: 10.1126/science.aag2981

This PDF file includes:

Materials and Methods Figs. S1 to S12 Tables S1 to S14 References

S2

Table of Contents General Experimental: Chemistry ................................................................................................. S5 Fig. S1 Preparation of (−)-BTX A/B- and D-ring building blocks ............................................... S6 Fig. S2 Total synthesis of (−)-batrachotoxin ............................................................................ S6−7 Fig. S3 Preparation of (+)-BTX A/B- and D-ring building blocks ............................................... S7 Fig. S4 Total synthesis of (+)-batrachotoxin ................................................................................ S7 Experimental Procedures and Characterization Data ............................................................. S8−30

Compound SI-1 ................................................................................................................. S8 Compound ent-SI-1 .......................................................................................................... S8 Compound SI-2 ................................................................................................................. S8 Compound SI-3 ................................................................................................................. S9 Compound SI-4 ........................................................................................................... S9−10 Compound SI-5 ............................................................................................................... S10 Compound ent-SI-5 ........................................................................................................ S10 Compound SI-6 ............................................................................................................... S11 Compound ent-SI-6 ........................................................................................................ S11 Compound SI-7 ............................................................................................................... S11 Compound SI-8 ............................................................................................................... S12 Compound SI-9 ......................................................................................................... S12−13 Compound SI-10 ............................................................................................................. S13 Compound SI-11 ....................................................................................................... S13−14 Compound ent-SI-11 ...................................................................................................... S14 Compound SI-12 ....................................................................................................... S14−15 Compound SI-13 ............................................................................................................. S15 Compounds 7 and 8 .................................................................................................. S15−16 Compound SI-14 ............................................................................................................. S16 Compound SI-15 ............................................................................................................. S17 Compound SI-16 ....................................................................................................... S17−18 Compound SI-17 ....................................................................................................... S18−19 Compound SI-18 ............................................................................................................. S19 Compound SI-19 ............................................................................................................. S20 Compound SI-20 ............................................................................................................. S21 Compound SI-21 ....................................................................................................... S21−22 Compound SI-22 ....................................................................................................... S22−23 Compound SI-23 ....................................................................................................... S23−24 Compound SI-24 ............................................................................................................. S24 Compound SI-25 ............................................................................................................. S25 Compound SI-26 ............................................................................................................. S26 (−)-Batrachotoxinin A ..................................................................................................... S27 (+)-Batrachotoxinin A ..................................................................................................... S27 Compound SI-27 ............................................................................................................. S28 (−)-Batrachotoxin ............................................................................................................ S28 (+)-Batrachotoxin ............................................................................................................ S29 Batrachotoxinin A 20-(R)-benzoate ................................................................................ S29

S3

ent-Batrachotoxinin A 20-(R)-benzoate .......................................................................... S30 1H and 13C NMR Spectra ...................................................................................................... S31−68

Compound SI-2 ............................................................................................................... S31 Compound SI-3 ............................................................................................................... S32 Compound SI-4 ............................................................................................................... S33 Compound SI-5 ............................................................................................................... S34 Compound SI-7 ............................................................................................................... S35 Compound SI-8 ............................................................................................................... S36 Compound SI-9 ............................................................................................................... S37 Compound SI-10 ............................................................................................................. S38 Compound SI-11 ............................................................................................................. S39 Compound SI-12 ............................................................................................................. S40 Compound SI-13 ............................................................................................................. S41 Compound 7 .............................................................................................................. S42−43 Compound 8 .............................................................................................................. S44−45 Compound SI-15 ............................................................................................................. S46 Compound SI-16 ....................................................................................................... S47−50 Fig. S5 1H NMR spectrum from the radical cyclization of SI-15 with Bu3SnD ............ S51 Compound SI-17 ............................................................................................................. S52 Compound SI-18 ............................................................................................................. S53 Compound SI-19 ............................................................................................................. S54 Compound SI-20 ............................................................................................................. S55 Compound SI-21 ............................................................................................................. S56 Compound SI-22 ............................................................................................................. S57 Compound SI-23 ............................................................................................................. S58 Compound SI-24 ............................................................................................................. S59 Compound SI-25 ............................................................................................................. S60 Compound SI-26 ........................................................................................................ S61-62 Batrachotoxinin A ........................................................................................................... S63 Kishi natural and synthetic BTX-A ................................................................................ S64 Batrachotoxin ............................................................................................................ S65−66 Batrachotoxinin A 20-(R)-benzoate .......................................................................... S67−68

HPLC Data for Natural and Synthetic BTX ......................................................................... S69−70 Comparison Table for Spectra .............................................................................................. S71−72

Table S1 Comparison of synthetic and natural batrachotoxinin A 13C NMR shifts. ...... S71 Table S2 Comparison of synthetic and natural batrachotoxinin 13C NMR shifts ........... S72

X-ray Data for SI-18 ............................................................................................................. S73−88 General Experimental: Electrohysiology .............................................................................. S89−90 Fig. S6 Electrophysiological comparison of BTX-B and (−)-BTX ................................ S91

Table S12 Summary of effects of 10 µM and 1 µM BTX-B and (−)-BTX on gating parameters of rNaV1.4 ..................................................................................................... S92

Fig. S7 Effects of BTX-B on selected NaV isoforms ...................................................... S93 Fig. S8 Effects of BTX-B on wild-type NaV current ...................................................... S94 Table S13 Summary of effects of BTX-B on gating parameters of rNaV1.4 ................. S94

Fig. S9 Amino acid sequence alignment of the predicted domain I-IV S6 helices in human NaV isoforms and rat NaV1.4 .............................................................................. S95

S4

Fig. S10 Dose-response curves for BTX-B and ent-BTX-B against rNaV1.4 ................ S96 Fig. S11 Effects of ent-BTX-B and (+)-BTX on wild-type rNaV1.4 .............................. S96 Table S14 Summary of effects of ent-BTX-B on gating parameters of rNaV1.4 ........... S97 Fig. S12 Effects of ent-BTX-B on wild-type rNaV1.4 and single-point mutants ........... S97

S5

General Experimental: Chemistry All reagents were obtained commercially unless otherwise noted. A 10 µg sample of natural (−)-BTX was purchased from Santa Cruz Biotech. Reactions were performed using flame-dried glassware under an atmosphere of dry nitrogen. Air- and moisture-sensitive liquids and solutions were transferred via syringe or stainless steel cannula. Organic solutions were concentrated under reduced pressure (~15 Torr) by rotary evaporation. Methanol was distilled from sodium methoxide. Dichloromethane (CH2Cl2), benzene, diethyl ether (Et2O), toluene, acetonitrile (CH3CN), and tetrahydrofuran (THF) were passed through columns of activated alumina immediately prior to use. Triethylamine (Et3N) and 1,4-dioxane were distilled from CaH2 immediately prior to use.

Chromatographic purification of products was accomplished using forced flow chromatography on Silicycle silica gel 60 (40–63 mm). In select cases as indicated, NH4OH pre-treated silica gel was used for chromatographic separation. This material was prepared by slurrying silica gel with concentrated aqueous NH4OH in a large crystallization dish followed by evaporation of water by heating at 50 °C on a hot plate overnight. Thin layer chromatography was performed on EM Science silica gel 60 F254 plates (250 mm). Visualization of the developed chromatogram was accomplished by fluorescence quenching and by staining with aqueous ceric ammonium molybdate (CAM) solution.

Nuclear magnetic resonance (NMR) spectra were acquired on a Varian Inova spectrometer operating at 400, 500 or 600 and 100, 125 or 150 MHz for 1H and 13C, respectively, and are referenced internally according to residual solvent signals. Data for 1H NMR are recorded as follows: chemical shift (δ, ppm), multiplicity (s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; br, broad), integration, coupling constant (Hz). Data for 13C NMR are reported in terms of chemical shift (δ, ppm). Infrared spectra were recorded as thin films using NaCl plates on a Thermo-Nicolet 300 FT-IR spectrometer and are reported in frequency of absorption. Optical rotation data were obtained from samples loaded into a 50 mm cell on a Jasco DIP-1000 digital polarimeter operating at the Na D-line. High-resolution mass spectra were obtained from the Vincent Coates Foundation Mass Spectrometry Laboratory at Stanford University.

Caution: Batrachotoxin and batrachotoxinin A 20α-benzoate are extremely potent neurotoxins (LD50 = 1–2 µg/kg; mouse, subcutaneous) and should be handled with great care. Both compounds are skin permeable and may cause paralysis and even death if contact with the skin occurs. Gloves should be worn at all times and these compounds should not be used if any cuts or open sores are present.

S6

Fig. S1 Preparation of (−)-BTX A/B- and D-ring building blocks. Reagents and conditions: (A) (a) m-CPBA, CH2Cl2, 0 °C (96%); (b) I2, PPh3, imidazole (90%); (c) Zn, AcOH, EtOH (99%); (d) IBX, DMSO (92%); (B) (e) H2, 2.5 mol% Pd/C, HCl, ethylene glycol (89%); (f) Et3SiOTf, Et3N, 0 °C (88%); (g) CHBr3, KOtBu, –25 °C (53%); (h) Me3SiC≡CLi, THF, (80%); (i) camphor sulfonic acid, MeOH (91%).

Fig. S2 Total synthesis of (−)-batrachotoxin. Reagents and conditions: (a) t-BuLi, THF, −90 °C, then SI-5 (65%); (b) K2CO3, MeOH (94%); (c) Me3SiC≡CSiEt2Cl SI-14, imidazole, CH2Cl2 (93%); (d) O2, n-Bu3SnH, Et3B, Ph2O, 150 °C (75%); (e) n-Bu4NF, THF, 60 °C (94%); (f) 2-iodoxybenzoic acid, t-BuOH, 65 °C then OsO4 (7 mol%), NaIO4, pyridine, H2O (53-61%); (g) MeNH2, CH2Cl2; NaB(O2CCF3)3H, CH2Cl2, −78 °C, then ClCH2COCl, 2,6-lutidine, −78 to 0 °C (49-54%); (h) NaOEt, EtOH, THF/C6H6 (1:1) (92%); (i) KN(SiMe3)2, PhNTf2, THF, −78 to 0 °C (94%); (j) CuCl2, O2, 1,4-dioxane, 73 °C (85%); (k) NaClO2, NaH2PO4, DMSO/H2O; (l) SOCl2, pyridine, CH2Cl2; (m) NaN3, acetone/H2O; (n) aqueous AcOH, 1,4-dioxane, 90 °C (57% over 4 steps); (o) p-TsOH, 4Å

Me

O

OMe

H

Br

SiMe3

OMeO

tBuMe2SiO

HO

tBuMe2SiO

O

a-d

SI-5SI-1 SI-6 SI-11

e-iA B

HOO

H

MeHO

O

NMe

MeO

Me

O

H

SiMe3

Br

MeO

Me

O

H

OSitBuMe2SiMe3

MeO

Me

O

H

OSitBuMe2

MeO

Me

O

H

Bu3SnOH

OH

SiMe3

MeO

Me

O

H

OHC O

OH

Bu3Sn

MeOO

H

Me O

NMe

O

Bu3SnOTf

MeOO

H

MeOHC

O

NMe

O OTf

OO

H

MeO

O

NMe

O OTf

OO

H

MeO

O

NMe

O O Me

(–)-Batrachotoxinin A

SI-11 SI-12 SI-15

SI-17 SI-18

SI-21 SI-22

SI-24: Ar = C6H4OMe SI-25: Ar = C6H4OMe

MeO

Me

O

H

OBu3SnOSitBuMe2Et2Si

SI-16

MeO

Me

O

H

O

OH

Bu3Sn

MeN

SI-19

HOO

H

MeO

O

NMe

O OTf

SI-23

OO

H

MeHO

O

NMe

SI-26: Ar = C6H4OMe

aOH

b-cO Si

Et2

SiMe3 d

HMe3Si

MeO

Me

O

H


SI-16

HMe3Si

e f g

OCl

MeO

Me

O

H

O

OH

Bu3Sn

MeN

SI-19

OCl

h-i j k-n

HOO

H

MeO

O

NMe

O OTf

SI-23

o p q

Ar Ar Ar

OHMe

MeOH

OO

H

MeHO

O

NMe

SI-26: Ar = C6H4OMeAr

OHMe

r s

(–)-Batrachotoxin

HOO

H

MeHO

O

NMe

OMe

O

NH

Me

MeEtO O

O O

NH

Me

Me

SI-27

S7

molecular sieves, p-methoxyphenethyl alcohol, C6H6 (89%); (p) LiCl, CuCl, Pd(PPh3)4, tributyl(1-ethoxyvinyl)tin, THF, 60 °C then 1 M oxalic acid, 0 °C (77%); (q) AlH3, THF, −78 to 0 °C (33%); (r) p-TsOH, 3:2 acetone/H2O (83%); (s) Et3N, C6H6, 45 °C (79%).

Fig. S3 Preparation of (+)-BTX A/B- and D-ring building blocks. Reagents and conditions: (A) (a) m-CPBA, CH2Cl2, 0 °C (96%); (b) I2, PPh3, imidazole (90%); (c) Zn, AcOH, EtOH (99%); (d) IBX, DMSO (92%); (B) (e) D-proline, DMF, 16 °C; (f) H2SO4, DMF, 95 °C (90% over 2 steps); (g) H2, 2.5 mol% Pd/C, HCl, ethylene glycol (89%); (h) Et3SiOTf, Et3N, 0 °C (88%); (i) CHBr3, KOtBu, –25 °C (53%); (j) Me3SiC≡CLi, THF, (80%); (k) camphor sulfonic acid, MeOH (91%).

Fig. S4 Total synthesis of (+)-batrachotoxin. Reagents and conditions: (a) t-BuLi, THF, −90 °C, (65%); (b) K2CO3, MeOH (94%); (c) Me3SiC≡CSiEt2Cl SI-14, imidazole, CH2Cl2 (93%); (d) O2, n-Bu3SnH, Et3B, Ph2O, 150 °C (75%); (e) n-Bu4NF, THF, 60 °C (94%); (f) 2-iodoxybenzoic acid, t-BuOH, 65 °C then OsO4 (7 mol%), NaIO4, pyridine, H2O (53-61%); (g) MeNH2, CH2Cl2; NaB(O2CCF3)3H, CH2Cl2, −78 °C, then ClCH2COCl, 2,6-lutidine, −78 to 0 °C (49-54%); (h) NaOEt, EtOH, THF/C6H6 (1:1) (92%); (i) KN(SiMe3)2, PhNTf2, THF, −78 to 0 °C (94%); (j) CuCl2, O2, 1,4-dioxane, 73 °C (85%); (k) NaClO2, NaH2PO4, DMSO/H2O; (l) SOCl2, pyridine, CH2Cl2; (m) NaN3, acetone/H2O; (n) aqueous AcOH, 1,4-dioxane, 90 °C (57% over 4 steps); (o) p-TsOH, 4Å molecular sieves, p-methoxyphenethyl alcohol, C6H6 (89%); (p) LiCl, CuCl, Pd(PPh3)4, tributyl(1-ethoxyvinyl)tin, THF, 60 °C then 1 M oxalic acid, 0 °C (77%); (q) AlH3, THF, −78 to 0 °C (33%); (r) p-TsOH, 3:2 acetone/H2O (83%); (s) Et3N, C6H6, 45 °C (79%).

Me

O

OMeOMe

O

O

ent-SI-6

OSitBuMe2

OH

ent-SI-1 ent-SI-11

OMe

Me

O

H

SiMe3

BrOSitBuMe2

Oent-SI-5

A B

a-d e-f g-k

OStBuMe2

Oent-SI-5 (+)-Batrachotoxin

OHO

H

MeOH

O

NMe

OMe

O

HN

Me

Me

(+)-Batrachotoxinin A

OHO

H

MeOH

O

NMe

HOMe

OEtO

OO

NH

Me

Me

SI-27ent-SI-11

OMe

Me

O

H

SiMe3

Bra-r s

S8

Experimental procedures and characterization data

SI-1. This compound was prepared as described in reference 21.

ent-SI-1. This compound was prepared as described in reference 21.

SI-2. To an ice-cold solution of allylic alcohol SI-1 (10.8 g, 47.3 mmol) and NaHCO3 (7.9g, 94.6 mmol, 2.0 equiv) in 250 mL of CH2Cl2 was added mCPBA (~70%, technical grade, 13.5g, 56.7 mmol, 1.2 equiv) in a single portion. The reaction was stirred for 4 h at 0 °C then quenched by the addition of 100 mL of saturated aqueous Na2S2O3. The reaction mixture was transferred to a separatory funnel with ~200 mL of CH2Cl2. The organic layer was separated, washed with 100 mL of 1M aqueous NaOH, dried over Na2SO4, filtered, and concentrated under reduced pressure to yield SI-2 as a colorless oil (11.1 g, 96%). This material was determined by 1H NMR to be sufficiently pure for use in the subsequent step. An analytically pure sample was obtained following chromatography on silica gel (30% EtOAc/hexanes); 1H NMR indicated this material to be a 1:1 diastereomeric mixture.

Note: Analytical data represents a 1:1 mixture of diastereomers. TLC Rf = 0.45 and 0.50 in 50% EtOAc/hexanes 1H NMR (400 MHz, CDCl3) δ 4.26 (d, J = 5.3 Hz, 1H), 4.21 (t, J = 7.9 Hz, 1H), 4.04-3.97 (m, 2H), 3.82 (m, 2H), 3.53 (s, 1H), 3.41 (s, 1H), 2.12-2.08 (m, 2H), 1.99 (dd, J = 14.0, 8.0 Hz, 1H), 1.93-1.62 (m, 4H), 1.58-1.37 (m, 3H), 0.85 (s, 9H), 0.85 (s, 9H), 0.06 (s, 3H), 0.04 (s, 6H), 0.02 (s, 3H) ppm. 13C NMR (100 MHz, CDCl3) δ 73.6, 72.5, 69.0, 67.9, 61.8, 59.5, 59.4, 58.8, 31.0, 28.2, 26.0 (3C), 25.9 (3C), 25.3, 24.9, 18.3, 18.2, -4.3, -4.4, -4.8, -4.9 ppm.

IR (thin film) ν 3446, 2954, 2929, 2886, 1463, 1472, 1361, 1257, 1170, 1107, 1071, 1045, 1006, 986, 949, 928, 889, 856 cm-1.

HRMS (ESI+) calcd for C12H24O3Si 244.1495 found 267.1392 (M+Na+).

tBuMe2SiO

HO

SI-1

OSitBuMe2

OH

ent-SI-1

tBuMe2SiO

HO

SI-2

O

S9

SI-3. To an ice-cold solution of epoxy alcohol SI-2 (11.1 g, 45.4 mmol), PPh3 (13.0 g, 49.6 mmol, 1.10 equiv) and imidazole (3.8 g, 54.5 mmol, 1.20 equiv) in 235 mL of a 3:1 Et2O/CH3CN mixture was added iodine (13.2 g, 52.0 mmol, 1.12 equiv) in a single portion. The reaction was stirred for 1 h at 0 °C then quenched by the addition of 120 mL of saturated aqueous Na2S2O3. The organic layer was diluted with 200 mL of hexanes, transferred to a separatory funnel with 50 mL of Et2O, and the organic phase was collected. The aqueous layer was extracted with 2 x 200 mL of 1:1 Et2O/hexanes. The combined organic fractions were washed with 200 mL of saturated aqueous NaCl, dried over MgSO4, filtered, and concentrated under reduced pressure to a white slurry. Purification of this material by chromatography on silica gel (5% EtOAc/hexanes) afforded SI-3 as a colorless oil (14.5 g, 90%); 1H NMR indicated this material to be a 1:1 diastereomeric mixture. Note: Analytical data represents a 1:1 mixture of diastereomers.

TLC Rf = 0.58 in 10% EtOAc/hexanes 1H NMR (400 MHz, CDCl3) δ 4.57 (t, J = 7.9 Hz, 1H), 4.24 (d, J = 5.0 Hz, 1H), 3.87 (d, J = 10.4 Hz, 1H), 3.62 (s, 1H), 3.56 (d, J = 10.3 Hz, 1H), 3.28 (s, 1H), 3.14 (d, J = 10.4 Hz, 1H), 3.09 (d, J = 10.3 Hz, 1H), 1.97-1.74 (m, 4H), 1.70-1.54 (m, 2H), 1.52-1.46 (m, 1H), 1.37 (ddt, J = 12.2, 10.7, 8.3 Hz, 1H), 0.87 (s, 9H), 0.86 (s, 9H), 0.14 (s, 3H), 0.10 (s, 3H), 0.07 (s, 3H), 0.05 (s, 3H) ppm. 13C NMR (100 MHz, CDCl3) δ 73.2, 71.4, 68.0, 67.9, 67.1, 63.1, 30.1, 28.4, 26.7, 26.1 (3C), 26.0 (3C), 24.9, 18.3, 18.1, 5.5, 1.3, -4.1, -4.2, -4.3, -4.5 ppm.

IR (thin film) ν 2954, 2929, 2886, 2857, 1472, 1463, 1361, 1258, 1170, 1120, 1065, 992, 955, 941, 927, 910, 884 cm-1.

SI-4. A gray suspension of epoxy iodide SI-3 (14.5 g, 40.9 mmol), AcOH (17 M, 4.8 mL, 82 mmol, 2.0 equiv) and Zn dust (10.7 g, 164 mmol, 4.0 equiv) in 150 mL of absolute EtOH was heated to 70 °C for 1 h. Following this time, the mixture was cooled to room temperature, diluted 100 mL of Et2O, and filtered through a pad of Celite. The flask and filter cake were rinsed with ~100 mL of Et2O, and the combined filtrates were concentrated under reduced pressure. The resulting colorless oil was then dissolved in 400 mL of Et2O and the ethereal layer was washed sequentially with 150 mL of 1N aqueous HCl, 150 mL of water, and 150 mL of saturated aqueous NaCl. The organic fraction was dried over MgSO4, filtered, and concentrated under reduced pressure to a colorless oil. Purification of this material by chromatography on silica gel (15% EtOAc/hexanes) afforded SI-4 as a colorless oil (9.4g, 99%); 1H NMR indicated this material to be a 1:1 diastereomeric mixture. Note: Analytical data represents a 1:1 mixture of diastereomers.

tBuMe2SiO

I

SI-3

O

tBuMe2SiO

SI-4

HO

S10

TLC Rf = 0.2 in 15% EtOAc/hexanes 1H NMR (400 MHz, CDCl3) δ 5.24-5.19 (m, 2H), 5.20-5.10 (m, 2H), 4.57-4.49 (m, 2H), 4.39-4.35 (m, 2H), 2.51-2.41 (m, 2H), 2.15-1.98 (m, 2H), 1.88-1.65 (m, 4H), 1.47-1.37 (m, 2H), 0.88 (s, 9H), 0.87 (s, 9H), 0.06 (s, 6H), 0.06 (s, 6H) ppm. 13C NMR (100 MHz, CDCl3) δ 157.3, 156.9, 110.2, 109.6, 74.0, 73.6, 72.7, 72.3, 32.6, 32.4, 31.9, 31.6, 26.1 (6C), 18.4 (2C), -4.37, -4.43, -4.48, -4.55 ppm.

IR (thin film) ν 3352, 2957, 2886, 2857, 1472, 1463, 1406, 1389, 1361, 1252, 1177, 1128, 1082, 1025, 1006, 989, 938 cm-1.

SI-5. To a stirred solution of allylic alcohol SI-4 (1.04 g, 4.55 mmol) in 15 mL of DMSO was added 2-iodoxybenzoic acid (1.53 g, 5.46 mmol, 1.2 equiv). The reaction was stirred for 2 h then cooled in an ice bath and diluted with 50 mL of CH2Cl2 and 30 mL of water. The reaction mixture was stirred for 30 min while warming to room temperature and was then filtered through a pad of Celite. The flask and filter cake were rinsed with 50 mL of CH2Cl2. The filtrate was transferred to a separatory funnel with 20 mL of CH2Cl2, diluted with 80 mL of water, and the organic phase was collected. The aqueous layer was extracted with 3 x 50 mL of CH2Cl2. The combined organic fractions were dried over Na2SO4, filtered, and concentrated under reduced pressure to a colorless oil. Purification of this material by chromatography on silica gel (15% EtOAc/hexanes) gave SI-5 as a colorless oil (905 mg, 90%). [α]D = -37.8 (c = 1.0, CHCl3)

TLC Rf = 0.46 in 15% EtOAc/hexanes 1H NMR (400 MHz, CDCl3) δ 6.03 (dd, J = 2.5, 1.2 Hz, 1H), 5.41 (dd, J = 2.3, 1.2 Hz, 1H), 4.73-4.68 (m, 1H), 2.49-2.40 (m, 1H), 2.25-2.14 (m, 2H), 1.77-1.66 (m, 1H), 0.87 (s, 9H), 0.08 (s, 6H) ppm. 13C NMR (100 MHz, CDCl3) δ 204.5, 148.7, 118.8, 72.6, 36.3, 31.1, 26.0 (3C), 18.3, -4.5, -4.3 ppm.

IR (thin film) ν 2956, 2930, 2886, 2858, 1732, 1648, 1463, 1389, 1362, 1118, 1066, 1006, 985, 940, 884 cm-1.

HRMS (ESI+) calcd for C12H22O2Si 226.1389 found 227.1462 (M+H+).

ent-SI-5. This compound was prepared from ent-SI-1 following the same sequence of steps used to prepare SI-5 from SI-1.

tBuMe2SiO

O

SI-5

OStBuMe2

Oent-SI-5

S11

SI-6. (S)-(+)-Hajos-Parrish diketone. This compound was prepared as described in reference 51.

ent-SI-6. (R)-(−)-Hajos-Parrish diketone. This compound was prepared as described in reference 51 using D-proline in place of L-proline.

SI-7. A solution of (S)-(+)-Hajos-Parrish diketone (35.9 g, 219 mmol) in 490 mL of ethylene glycol was charged with 5% Pd/C (12.0 g, 2.5 mol%). To the black suspension was then added sequentially 243 mL of THF and concentrated HCl (1.5 mL, 18 mmol, 0.08 equiv). The mixture was sparged with H2 gas for 15 min. The flask was then fitted with a balloon of H2 and the contents were stirred until TLC (40% EtOAc/hexanes) indicated the reaction was complete (~72 h). The suspension was then sparged with N2 gas for 15 min, diluted with 400 mL of CH2Cl2 and filtered through a pad of Celite. The filter cake was rinsed with 100 mL of CH2Cl2 and the filtrate was transferred to a separatory funnel with 100 mL of CH2Cl2 and partitioned with 600 mL of water. The organic fraction was collected and the aqueous layer was extracted with 2 x 500 mL of CH2Cl2. The combined organic extracts were dried over Na2SO4, filtered, and concentrated under reduced pressure to a colorless oil. Purification of this material by chromatography on silica gel (gradient elution: 25→30% EtOAc/hexanes) afforded SI-7 (see reference 52) as a colorless oil (40.8 g, 89%). TLC Rf = 0.48 (50% EtOAc/hexanes) 1H NMR (500 MHz, CDCl3) δ 3.92-3.86 (m, 4H), 2.27-2.23 (m, 2H), 2.13 (ddd, J = 9.5, 6.5, 3.7 Hz, 1H), 2.03-1.96 (m, 1H), 1.89 (dd, J = 9.7, 7.0 Hz, 1H), 1.85-1.75 (m, 2H), 1.56-1.53 (m, 1H), 1.41-1.34 (m, 3H), 1.00 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 221.7, 108.4, 64.3, 64.1, 48.0, 42.2, 35.9, 34.3, 31.0, 28.0, 23.6, 21.7 ppm. IR (thin film) ν 2954, 2883, 1737, 1471, 1451, 1409, 1364, 1285, 1252, 1185, 1109, 1049, 1029, 1002, 976, 947 cm-1.

Me O

SI-6O

Me

O

O

ent-SI-6

Me O

SI-7H

O

O

S12

SI-8. To a stirred solution of SI-7 (40.8 g, 194 mmol) in 390 mL of CH2Cl2 was added Et3N (54.1 mL, 388 mmol, 2 equiv). The reaction mixture was cooled to 0 °C and triethylsilyl trifluoromethanesulfonate (46 mL, 204 mmol, 1.05 equiv) was added dropwise via syringe over 5 min. The reaction mixture was stirred for 30 min and was then quenched by the addition of 400 mL of water. The biphasic solution was transferred to a separatory funnel with 100 mL of CH2Cl2, the organic fraction was collected, and the aqueous layer was extracted with 3 x 300 mL of CH2Cl2. The combined organic extracts were dried over Na2SO4, filtered, and concentrated under reduced pressure to a clear oil. Purification of this material by chromatography on silica gel (5% Et2O/hexanes) afforded SI-8 as a colorless oil (55.1 g, 88%). [α]D = +26.4 (c = 1.0, CHCl3)

TLC Rf = 0.42 (20% Et2O/hexanes) 1H NMR (500 MHz, CDCl3) δ 4.35 (t, J = 2.3 Hz, 1H), 3.89-3.87 (m, 4H), 2.28 (ddd, J = 14.4, 6.8, 2.1 Hz, 1H), 1.99-1.94 (m, 1H), 1.84 (ddd, J = 14.4, 3.8, 2.7 Hz, 1H), 1.77 (td, J = 8.2, 3.2 Hz, 1H), 1.68 (ddd, J = 13.8, 6.3, 1.6 Hz, 1H), 1.57-1.51 (m, 2H), 1.48-1.39 (m, 2H), 0.98 (s, 3H), 0.94 (t, J = 8.0 Hz, 9H), 0.68-0.63 (m, 6H) ppm. 13C NMR (125 MHz, CDCl3) δ 160.1, 109.7, 96.5, 64.23, 64.18, 44.8, 42.4, 37.0, 32.4, 31.5, 30.2, 24.3, 6.9 (3C), 5.0 (3C) ppm. IR (thin film) ν 2954, 2876, 1635, 1242, 1190, 1152, 1129, 1110, 1086, 1057, 1002 cm-1.

SI-9. To a stirred solution of silyl enol ether SI-8 (5.0 g, 15.4 mmol) in 100 mL of hexanes was added potassium tert-butoxide (13.9 g, 123.5 mmol, 8 equiv). The suspension was cooled to –25 °C in a dry ice/acetone bath (note: the bath temperature was held between –20 and –30 °C throughout the course of the reaction). A solution of CHBr3 (10.8 mL, 123.5 mmol, 8 equiv) in 30 mL of hexanes was added dropwise via syringe pump over 30 min during which time the suspension turned dark reddish-brown. After stirring for 2.5 h at –25 °C, the reaction was quenched by the addition of 75 mL of saturated aqueous NH4Cl. The mixture was transferred to a separatory funnel with 100 mL of Et2O. The organic fraction was collected and the aqueous layer was extracted with 3 x 75 mL of Et2O. The combined organic extracts were washed with 100 mL of saturated aqueous NaCl, dried over MgSO4, filtered, and concentrated under reduced pressure. The red-orange oil was purified by chromatography on silica gel (40% Et2O/hexanes) to afford SI-9 (see reference 20) as an orange oil that crystallized upon standing at –20 °C (2.47 g, 53%).

TLC Rf = 0.38 (60% Et2O/hexanes) 1H NMR (500 MHz, CDCl3) δ 7.11 (ddd, J = 6.2, 2.6, 1.3 Hz, 1H), 3.83-3.79 (m, 4H), 2.77 (ddd, J = 19.7, 5.7, 2.6 Hz, 1H), 2.25 (dt, J = 13.2, 3.4 Hz, 1H), 2.18-2.14 (m, 1H), 2.05 (ddd, J =

Me OSiEt3

SI-8H

O

O

Me

SI-9H

O

O

OBr

S13

19.7, 6.3, 1.6 Hz, 1H), 1.58 (t, J = 13.2 Hz, 1H), 1.51-1.45 (m, 2H), 1.37 (td, J = 13.4, 4.0 Hz, 1H), 1.27 (td, J = 13.4, 3.9 Hz, 1H), 1.10 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 194.9, 147.1, 122.0, 108.7, 64.50, 64.48, 47.5, 40.1, 37.8, 32.2, 32.1, 31.9, 24.4 ppm.

IR (thin film) ν 2948, 1687, 1608, 1434, 1367, 1329, 1245, 1186, 1121, 1090, 1057, 1030, 996, 968, 947, 916 cm-1.

SI-10. Trimethylsilylacetylene (11 mL, 77 mmol, 2.0 equiv) was dissolved in 100 mL of THF and the solution was cooled to –78 °C. A solution of n-butyllithium (2.45 M in hexanes, 28.3 mL, 1.8 equiv) was added dropwise and the mixture was stirred for 45 min at –78 °C. A solution of lithium bromide in THF (0.68 M, 102 mL, 1.8 equiv) was then added via cannula followed by dropwise addition of a solution of SI-9 (11.6 g, 38.5 mmol) in 60 mL of THF. The reaction mixture was then warmed to 0 °C with an ice bath, and the reaction progress monitored by TLC (15% EtOAc/hexanes). Upon completion (~1 h), the reaction was quenched at 0 °C by the addition of 100 mL of saturated aqueous NH4Cl and transferred to a separatory funnel with 100 mL of EtOAc. The organic fraction was collected and the aqueous layer was extracted with 3 x 150 mL of EtOAc. The combined organic extracts were washed with 200 mL of saturated aqueous NaCl, dried over MgSO4, filtered, and concentrated under reduced pressure. The red-orange oil was purified by chromatography on silica gel (25% Et2O/hexanes) to afford SI-10 (see reference 20) as pale yellow foam (12.3 g, 80%). TLC Rf = 0.46 (30% EtOAc/hexanes)

1H NMR (500 MHz, CDCl3) δ 6.06 (t, J = 4.1 Hz, 1H), 3.97-3.88 (m, 4H), 2.71 (s, 1H), 2.56-2.49 (m, 1H), 2.23-2.18 (m, 1H), 2.11 (dt, J = 12.0, 6.1 Hz, 1H), 2.05-1.99 (m, 1H), 1.81-1.69 (m, 4H), 1.59 (dt, J = 13.4, 6.3 Hz, 1H), 1.29 (s, 3H), 0.18 (s, 9H) ppm. 13C NMR (125 MHz, CDCl3) δ 129.9, 125.8, 109.4, 106.5, 90.8, 64.5 (2C), 63.8, 41.3, 36.2 (2C), 35.9, 32.2, 30.4, 30.0, 0.1 (3C) ppm. IR (thin film) ν 3421, 2958, 2166, 1430, 1367, 1250, 1162, 1098, 1015, 965, 947, 908, 843 cm-1.

SI-11. To a stirred solution of ketal SI-10 (12.3 g, 30.8 mmol) in 200 mL of MeOH was added (1S)-(+)-10-camphorsulfonic acid (720 mg, 3.1 mmol, 0.1 equiv). The reaction was stirred for 45 min, then quenched by the addition of 5 mL of Et3N and concentrated under reduced pressure.

Me

SI-10H

O

O

Br

SiMe3

OH

Me

H

Br

SiMe3

OMeO

SI-11

S14

Purification of this material by chromatography on silica gel (10% EtOAc/hexanes) furnished SI-11 (see reference 20) as a pale yellow oil that crystallized to an off-white solid (10.4 g, 91%).

[α]D = −12.8 (c = 1.0, CHCl3) TLC Rf = 0.58 (30% EtOAc/hexanes) 1H-NMR (500 MHz, CDCl3) δ 6.10 (ddd, J = 5.8, 2.2, 0.8 Hz, 1H), 3.33 (s, 3H), 2.42 (ddd, J = 18.2, 4.3, 2.2 Hz, 1H), 2.25 (td, J = 12.7, 5.4 Hz, 1H), 2.02-1.93 (m, 3H), 1.91-1.84 (m, 2H), 1.73 (ddd, J = 13.1, 5.3, 3.9 Hz, 1H), 1.61 (td, J = 12.2, 5.3 Hz, 1H), 1.52 (ddd, J = 13.2, 12.0, 3.3 Hz, 1H), 1.00 (s, 3H), 0.19 (s, 9H) ppm.

13C NMR (125 MHz, CDCl3) δ 127.5, 126.1, 103.5, 98.3, 91.6, 79.8, 50.0, 35.6, 35.3, 33.1, 32.8, 31.8, 30.8, 20.6, -0.1 (3C) ppm.

IR (thin film) ν 2963, 2171, 1630, 1466, 1434, 1356, 1341, 1319, 1250, 1203, 1184, 1127, 1103, 1069, 982, 960, 869 cm-1.

ent-SI-11. This compound was prepared from ent-SI-6 following the same sequence of steps used to prepare SI-11 from SI-6.

SI-12. To a –78 °C stirred solution of vinyl bromide SI-11 (2.50 g, 6.77 mmol) in 54 mL of THF was added tert-butyllithium (1.39 M in pentane, 10.2 mL, 2.1 equiv) dropwise via a 24 mL gas tight syringe over 5 min. The mixture was stirred at –78 °C for 45 min then transferred to a –90 °C liquid N2/heptane bath. A solution of enone SI-5 (1.84 g, 8.1 mmol, 1.2 equiv) in 13.5 mL of THF was added slowly (~7 min addition time) via syringe down the side of the reaction flask. The reaction mixture was stirred for 1 h while slowly warming to –78 °C and was then quenched by the addition of 100 mL of saturated aqueous NH4Cl. After warming to room temperature, the solution was transferred to a separatory funnel with 150 mL of EtOAc. The organic layer was collected and the aqueous fraction was extracted with 3 x 75 mL of EtOAc. The combined organic extracts were washed with 100 mL of saturated aqueous NaCl, dried over MgSO4, filtered, and concentrated under reduced pressure to a yellow oil. Purification of this material by chromatography on silica gel (gradient elution: 15→20% EtOAc/hexanes) gave SI-12 as colorless oil/foam (2.28 g, 65%).

[α]D = +91.9 (c = 1.0, CHCl3) TLC Rf = 0.33 (30% EtOAc/hexanes)

ent-SI-11

OMe

Me

O

H

SiMe3

Br

MeO

Me

O

H

OSitBuMe2SiMe3

SI-12

OH

S15

1H NMR (400 MHz, CDCl3) δ 5.98 (ddd, J = 5.5, 2.1, 0.8 Hz, 1H), 5.10 (dd, J = 2.0, 0.6 Hz, 1H), 5.06 (dd, J = 2.3, 0.6 Hz, 1H), 4.60 (ddt, J = 8.6, 6.6, 2.1 Hz, 1H), 3.24 (s, 3H), 2.63 (br s, 1H), 2.50-2.39 (m, 2H), 2.26 (td, J = 12.7, 5.5 Hz, 1H), 2.04-1.74 (m, 7H), 1.70-1.57 (m, 2H), 1.40 (ddd, J = 13.4, 12.1, 4.1 Hz, 1H), 0.89 (s, 9H), 0.87 (s, 3H), 0.12 (s, 9H), 0.08 (s, 3H), 0.08 (s, 3H) ppm. 13C NMR (100 MHz, CDCl3) δ 161.2, 141.8, 122.4, 109.2, 105.7, 97.8, 92.1, 81.5, 76.1, 75.4, 49.8, 37.0, 35.6, 33.9, 33.4, 33.1, 31.4, 31.2, 31.0, 26.1 (3C), 20.9, 18.3, -0.1 (3C), -3.9, -4.4 ppm.

IR (thin film) ν 3471, 2958, 2896, 2858, 2162, 1472, 1464, 1436, 1388, 1376, 1359, 1327, 1250, 1197, 1144, 1119, 1064, 1038, 999, 973, 943, 885 cm-1.

HRMS (ESI+) calcd for C29H48O4Si2 516.3091 found 539.2983 (M+Na+).

SI-13. To a solution of TMS-protected alkyne SI-12 (4.1 g, 7.94 mmol) in 80 mL of MeOH was added anhydrous potassium carbonate (2.74 g, 19.8 mmol, 2.5 equiv). The reaction was stirred for 1.5 h, then diluted with 200 mL of CH2Cl2 and poured into a separatory funnel containing 200 mL of H2O. The organic phase was collected and the aqueous layer was extracted with 3 x 100 mL of CH2Cl2. The combined organic extracts were dried over Na2SO4, filtered, and concentrated under reduced pressure to a viscous oil. Purification of this material by chromatography on silica gel (gradient elution: 10→15% EtOAc/hexanes) gave SI-13 as a colorless foam (3.312 g, 94%). TLC Rf = 0.33 (30% EtOAc/hexanes) 1H NMR (500 MHz, CDCl3) δ 6.14 (ddd, J = 5.6, 2.2, 0.8 Hz, 1H), 5.15 (d, J = 2.2, 1H), 5.11 (d, J = 2.6, 1H), 4.76 (ddt, J = 9.4, 7.0, 2.4 Hz, 1H), 3.28 (s, 3H), 2.52-2.46 (m, 3H), 2.35-2.29 (m, 2H), 2.08-1.83 (m, 7H), 1.73-1.62 (m, 2H), 1.48 (ddd, J = 13.5, 12.2, 4.1 Hz, 1H), 0.95 (s, 9H), 0.93 (s, 3H), 0.13 (s, 3H), 0.12 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 162.0, 141.2, 122.2, 108.6, 97.7, 83.7, 81.1, 75.9, 75.7, 75.4, 49.7, 36.1, 35.7, 33.7, 33.4, 33.0, 31.03, 31.01, 30.8, 26.1 (3C), 20.6, 18.5, -4.4, -4.5 ppm. IR (thin film) ν 3473, 2956, 2109, 1462, 1359, 1251, 1102, 886 cm-1.

7 and 8. A 100 mL round bottom flask was charged with alkyne SI-13 (200 mg, 0.45 mmol), n-Bu3SnH (480 µL, 1.78 mmol, 4.0 equiv), and 45 mL of toluene. The flask was stoppered with a

MeO

Me

O

H

OSitBuMe2

SI-13

OH

MeO

Me

O

H

OSitBuMe2H

OH

Bu3Sn

7

MeO

Me

O

H

OSitBuMe2Me

OH

Bu3Sn

8

S16

rubber septum, purged with N2 for 1 min, and the contents were heated to 80 °C. Upon reaching this temperature, a 1 mL syringe filled with 750 µL of air was injected into the reaction flask, followed by dropwise addition (30 s) of a solution of Et3B (1.0 M hexanes, 900 µl, 2.0 equiv). The reaction mixture was stirred at 80 °C until TLC (10% EtOAc/hexanes) indicated complete consumption of starting material (~1 h). The colorless solution was cooled to room temperature and concentrated under reduced pressure to a colorless oil. The unpurified product was dissolved in 10 mL of hexanes and transferred to a silica gel column pre-packed with a 15% toluene/hexanes solution. The column was initially eluted with 15% toluene/hexanes (~75 mL) to remove organotin impurities. Subsequent gradient elution with 8→15% Et2O/hexanes gave 8 (higher Rf product, 149 mg, 45%) and 7 (lower Rf product, 151 mg, 46%) as colorless oils.

7:

TLC Rf = 0.46 in 40% Et2O/hexanes 1H NMR (500 MHz, CDCl3) δ 6.17 (s, JSn-H = 68.1 Hz, 1H), 6.07 (dd, J = 5.0, 2.1 Hz, 1H), 4.05 (ddd, J = 4.6, 2.8, 1.6 Hz, 1H), 3.43 (s, 1H), 3.30 (s, 3H), 2.63 (ddd, J = 14.9, 9.9, 5.3 Hz, 1H), 2.51-2.37 (m, 2H), 2.10 (d, J = 10.4 Hz, 1H), 2.03-1.93 (m, 2H), 1.93-1.63 (m, 9H), 1.62-1.43 (m, 6H), 1.34 (m, 6H), 1.23 (ddd, J = 13.5, 12.0, 3.7 Hz, 1H), 1.04-0.85 (m, 24H), 0.76 (s, 3H), 0.11 (s, 3H), 0.11 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 154.1, 142.1, 127.8, 118.7, 98.0, 82.5 (2C), 81.3, 58.9, 49.8, 37.5, 37.2, 35.9, 35.3, 35.2, 33.0, 31.9, 30.8, 29.6 (JSn-H = 19.7 Hz, 3C), 29.2, 27.7 (JSn-H = 56.7 Hz, 3C), 26.1 (3C), 21.4, 18.2, 14.0 (3C), 10.8 (JSn-H = 337.9, 303.0 Hz, 3C), −4.2, −4.4 ppm. IR (thin film) ν 3462 (br), 2956, 2928, 2855, 1464, 1376, 1343, 1255, 1144, 1078, 967 cm-1.

8: TLC Rf = 0.54 in 40% Et2O/hexanes 1H NMR (500 MHz, CDCl3) δ 6.86 (s, JSn-H = 114.3, 109.2 Hz, 1H), 5.92 (ddd, J = 4.5, 2.6, 0.8 Hz, 1H), 4.37 (dd, J = 6.8, 4.0 Hz, 1H), 3.25 (s, 3H), 2.63 (ddd, J = 13.5, 11.9, 4.5 Hz, 1H), 2.32 (ddd, J = 18.5, 4.7, 2.6 Hz, 1H), 2.20-2.06 (m, 3H), 1.97-1.83 (m, 4H), 1.82-1.13 (m, 22H), 1.01-0.80 (m, 21H), 0.71 (d, J = 11.5 Hz, 1H), 0.71 (s, 1H), 0.68 (s, 3H), 0.09 (s, 3H), 0.06 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 168.1, 153.6, 129.7, 119.7, 98.2, 85.3, 83.0, 81.6, 72.3, 49.7, 40.9, 37.3, 36.4, 32.4, 31.9, 31.5, 31.4, 31.0, 29.6, 29.5, 29.4 (2C), 27.6, 27.4 (2C), 26.6 (3C), 20.9, 18.8, 14.1, 13.9 (2C), 13.5, 11.8, 10.9, −3.5, −3.8 ppm.

IR (thin film) ν 3460 (br), 2956, 2927, 2855, 1465, 1377, 1342, 1250, 1146, 1077, 973 cm-1.

SI-14. Chlorodiethyl((trimethylsilyl)ethynyl)silane. This compound was prepared as described in reference 30.

SI-14

SiEt2ClMe3Si

S17

SI-15. To a solution of alcohol SI-13 (6.55 g, 14.7 mmol) in 300 mL of CH2Cl2 were added imidazole (4.00 g, 59 mmol, 4 equiv) and SI-14 (6.4 mL, 22 mmol, 1.5 equiv). The reaction mixture was stirred for 2.5 h, then quenched by the addition of 150 mL of H2O and transferred to a separatory funnel with 50 mL of CH2Cl2. The organic phase was collected and the aqueous layer was extracted with 3 x 150 mL of CH2Cl2. The combined organic fractions were dried over Na2SO4, filtered, and concentrated under reduced pressure to a colorless oil. Purification of this material by chromatography on silica gel (10% Et2O/hexanes) afforded SI-15 as a white crystalline solid (8.80 g, 93%). TLC Rf = 0.58 in 20% Et2O/hexanes 1H NMR (500 MHz, CDCl3) δ 6.26 (dd, J = 5.1, 1.7 Hz, 1H), 5.25 (d, J = 2.6 Hz, 1H), 5.14 (d, J = 2.1 Hz, 1H), 4.83 (ddd, J = 10.1, 7.3, 2.5 Hz, 1H), 3.29 (s, 3H), 2.61 (td, J = 13.1, 7.0 Hz, 1H), 2.50 (ddd, J = 18.4, 4.7, 2.1 Hz, 1H), 2.45 (s, 1H), 2.30 (td, J = 12.8, 4.8 Hz, 1H), 2.04-1.89 (m, 6H), 1.85 (t, J = 12.0 Hz, 1H), 1.76-1.61 (m, 2H), 1.45 (ddd, J = 13.5, 12.1, 4.4 Hz, 1H), 1.08-0.94 (m, 15H), 0.91 (s, 3H), 0.88-0.80 (m, 1H), 0.73-0.67 (m, 3H), 0.17 (s, 9H), 0.09 (s, 3H), 0.08 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 157.9, 139.9, 122.1, 114.0, 112.8, 111.6, 97.5 (2C), 84.3, 83.7, 76.4, 75.7, 74.9, 49.7, 36.0, 35.5, 33.9, 33.5, 32.9, 31.1, 30.9, 26.0 (3C), 20.4, 18.2, 7.9, 7.8, 7.1, 7.0, 0.0 (3C), -4.2, -4.6 ppm. IR (thin film) ν 3308, 2958, 2896, 2858, 1463, 1436, 1409, 1377, 1358, 1346, 1326, 1250, 1198, 1140, 1120, 1103, 1049, 1034, 1005, 975, 950, 898 cm-1. HRMS (ESI+) calcd for C35H58O4Si3 626.3643 found 649.3535 (M+Na+).

SI-16. A 1 L round bottom flask was charged with alkyne SI-15 (2.25 g, 3.67 mmol) and 320 mL of diphenyl ether, which had been sparged with N2 for 15 min. The flask was stoppered with a rubber septum, purged with N2 for 1 min, then heated to 150 °C. Upon reaching this temperature, n-Bu3SnH (4.3 mL, 14.7 mmol, 4 equiv) was added via syringe. A 5 mL syringe was filled with 3 mL of air and injected into the reaction flask, followed by dropwise addition (30 s) of a solution of Et3B (1M hexanes, 7.3 mL, 2 equiv). The reaction mixture was stirred at 150 °C until TLC (10% EtOAc/hexanes) indicated complete consumption of starting material (~1 h). The colorless solution was cooled to ~100 °C and the hot solvent removed under high vacuum (~1 Torr). The resulting colorless oil was diluted with ~150 mL of hexanes and poured onto a silica gel column that was packed with 15% toluene/hexanes. The column was initially eluted with 15% toluene/hexanes (~400 mL) to remove organotin impurities. Subsequent

MeO

Me

O

H

OSitBuMe2

SI-15

O SiEt2

SiMe3

MeO

Me

O

H


SI-16

HMe3Si

S18

gradient elution with 3→5% Et2O/hexanes gave SI-16 as a colorless oil that crystallized upon standing at –20 °C (2.46 g, 75%).

[α]D = −28.2 (c = 1.0, CHCl3) TLC Rf = 0.65 in 20% Et2O/hexanes 1H NMR (500 MHz, CDCl3) δ 6.24 (s, 1H), 6.11 (ddd, J = 5.2, 3.5, 1.2 Hz, 1H), 5.54 (t, JSn-H = 7.5 Hz, 1H), 4.00 (t, J = 7.7 Hz, 1H), 3.23 (s, 3H), 2.51 (ddd, J = 14.2, 11.8, 2.6 Hz, 1H), 2.33 (td, J = 13.6, 7.0 Hz, 1H), 2.25 (ddd, J = 18.1, 4.5, 2.1 Hz, 1H), 2.14 (d, J = 14.1 Hz, 1H), 2.12-2.06 (m, 1H), 2.01-1.82 (m, 5H), 1.79-1.74 (m, 2H), 1.66 (m, 2H), 1.59-1.46 (m, 7H), 1.35 (m, 6H), 1.14-1.11 (m, 7H), 0.97-0.91 (m, 15H), 0.88 (s, 9H), 0.85-0.76 (m, 2H), 0.62-0.56 (m, 4H), 0.07 (s, 9H), 0.04 (s, 3H), 0.02 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 164.1, 142.8, 141.6, 136.4 (JSn-C = 16.3 Hz), 134.7 (JSn-C = 21.5 Hz), 121.2, 97.6, 89.5, 85.0, 80.1, 65.3, 49.5, 38.3, 37.0, 35.57, 35.55, 35.3, 33.3, 32.0, 30.3, 29.4 (3C, JSn-C = 9.5 Hz), 27.6 (3C, JSn-C = 26.9 Hz), 26.2 (3C), 18.8, 18.6, 15.3, 13.9 (3C), 10.3 (3C, JSn-C = 156.7, 149.8 Hz), 9.8, 7.71, 7.68, 6.8, 0.1 (3C), -4.3 (2C) ppm.

IR (thin film) ν 2955, 2928, 1464, 1376, 1248, 1085, 1047, 976 cm-1.

SI-17. To a solution of SI-16 (2.111 g, 2.30 mmol) in 6.0 mL of THF was added via syringe a solution of Bu4NF (1.0 M in THF, 14 mmol, 6.0 equiv). The reaction mixture was stirred at 60 °C until TLC (40% Et2O/hexanes) indicated complete consumption of starting material (~14 h). The reaction was cooled to room temperature and quenched by the addition of 20 mL of saturated aqueous NH4Cl. The contents were transferred to a separatory funnel with 30 mL of Et2O and the mixture extracted with 3 x 100 mL of Et2O. The organic fraction was washed successively with 150 mL of H2O and 150 mL of saturated aqueous NaCl, dried over MgSO4, filtered, and concentrated under reduced pressure to a yellow oil. Purification of this material by chromatography on silica gel (gradient elution: 8→12% EtOAc/hexanes) furnished SI-17 as a white crystalline solid (1.554 g, 94%). [α]D = −64.5 (c = 1.0, CHCl3)

TLC Rf = 0.37 in 40% Et2O/hexanes 1H NMR (500 MHz, CDCl3) δ 6.17 (d, J = 19.5 Hz, 1H), 5.99 (ddd, J = 5.1, 3.1, 1.2 Hz, 1H), 5.73 (d, J = 19.5 Hz, 1H), 5.00 (t, JSn-H = 7.5 Hz, 1H), 4.06 (t, J = 5.5 Hz, 1H), 3.26 (s, 3H), 3.16 (s, 1H), 2.89 (ddd, J = 14.2, 12.0, 4.8 Hz, 1H), 2.82 (d, J = 5.6 Hz, 1H), 2.43 (ddd, J = 14.4, 11.7, 3.0 Hz, 1H), 2.33 (ddd, J = 18.2, 4.6, 2.2 Hz, 1H), 2.11-1.97 (m, 3H), 1.94-1.86 (m, 4H), 1.84-1.78 (m, 3H), 1.76-1.69 (m, 1H), 1.53-1.47 (m, 6H), 1.32 (m, 6H), 0.95-0.85 (m, 15H), 0.65 (s, 3H), 0.03 (s, 9H) ppm. 13C NMR (125 MHz, CDCl3) δ 143.9, 141.9 (JSn-C = 16.5 Hz), 140.0, 133.7, 130.1, 120.5, 97.9, 83.8, 83.0, 80.8, 61.3, 49.7, 37.8, 36.8, 35.3, 35.0, 33.5, 32.1, 31.4, 30.6, 29.41 (3C, JSn-C = 9.7

MeO

Me

O

H

Bu3SnOH

OH

SiMe3

SI-17

S19

Hz), 27.7 (3C, JSn-C = 27.6 Hz), 19.9, 15.0, 14.0 (3C), 10.4 (3C, JSn-C = 156.9, 150.0 Hz), -0.9 (3C) ppm.

IR (thin film) ν 3288, 2954, 2925, 2854, 2242, 1611, 1464, 1435, 1377, 1360, 1318, 1287, 1256, 1244, 1213, 1146, 1085, 1050, 1031, 1018, 998, 979, 951, 926, 908, 883 cm-1.

HRMS (ESI+) calcd for C37H64O4SiSn 720.3596 found 743.3491 (M+Na+).

SI-18. To a solution of alcohol SI-17 (400.0 mg, 0.56 mmol) in 30 mL of tert-butanol was added 2-iodoxybenzoic acid (470 mg, 1.68 mmol, 3 equiv). The solution was heated to 75 °C until TLC (3:1:1 hexanes/EtOAc/CH2Cl2) indicated complete consumption of the starting material (~12 h). The reaction mixture was cooled to room temperature and diluted with 30 mL of H2O. Sodium periodate (480 mg, 2.24 mmol, 4 equiv), pyridine (160 µL, 2.0 mmol, 3.6 equiv), and OsO4 (4% aqueous, 270 µL, 7 mol %) were added sequentially and the mixture was stirred until TLC (30% EtOAc/hexanes) indicated complete consumption of the starting material (~24 h). Following this time, the solution was cooled 0 °C, diluted with 10 mL of EtOAc, and the reaction was quenched by the addition of 20 mL of 1.0 M aqueous ascorbic acid. The mixture was stirred vigorously for 15 min while warming to room temperature, then transferred to a separatory funnel with 30 mL of EtOAc. The organic layer was collected and the aqueous phase was extracted with 3 x 50 mL of EtOAc. The combined organic extracts were washed sequentially with 50 mL each of saturated aqueous NaHCO3, H2O, and saturated aqueous NaCl, dried over MgSO4, filtered, and concentrated under reduced pressure to a brown oil. Purification of this material by chromatography on silica gel (15% EtOAc/hexanes) gave SI-18 as a pale yellow oil that crystallized upon standing (220 mg, 61%; yield varies between 53–61%).

TLC Rf = 0.33 in 20% EtOAc/hexanes 1H NMR (500 MHz, CDCl3) δ 9.56 (s, 1H), 6.23 (ddd, J = 5.3, 2.3, 1.1 Hz, 1H), 5.17 (t, JSn-H = 7.5 Hz, 1H), 3.83 (d, J = 1.9 Hz, 1H), 3.25 (s, 3H), 2.77-2.68 (m, 2H), 2.48-2.34 (m, 3H), 2.18 (dt, J = 13.2 Hz; JSn-H = 30.2 Hz, 1H), 2.07-2.04 (m, 1H), 1.98-1.89 (m, 3H), 1.84-1.72 (m, 5H), 1.52-1.45 (m, 6H), 1.35-1.29 (m, 6H), 0.93-0.88 (m, 15H), 0.62 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 212.4, 200.0, 150.8 (JSn-C = 18.2 Hz), 140.0, 122.2, 117.2 (JSn-C = 19.0 Hz), 98.0, 80.89, 80.87, 71.6, 49.6, 38.0, 36.7, 35.6, 34.8, 33.4, 32.1, 31.9, 30.5, 29.3 (3C, JSn-C = 9.7), 27.7 (3C, JSn-C = 51.9, 28.3 Hz), 19.2, 16.2, 13.9 (3C), 10.5 (3C, JSn-C = 158.7, 151.8 Hz) ppm. IR (thin film) ν 3450, 2956, 2926, 2852, 1743, 1710, 1646, 1435, 1377, 1348, 1254, 1195, 1148, 1076, 980, 927 cm-1.

MeO

Me

O

H

OHC O

OH

Bu3Sn

SI-18

S20

SI-19. To a solution of aldehyde SI-18 (645 mg, 1.0 mmol) in 17 mL of CH2Cl2 was added a solution of MeNH2 (2.0 M in THF, 2.4 mL, 4.8 mmol, 4.8 equiv). The reaction mixture was stirred for 2 h then diluted with 3 mL of anhydrous toluene and concentrated under reduced pressure to a pale yellow oil. The unpurified material was re-dissolved in 15 mL of CH2Cl2 and the solution was cooled to –78 °C. A solution of freshly prepared NaBH(O2CCF3)3 (0.5 M in THF, 3.1 mL, 1.5 equiv; prepared by dropwise addition of 3.0 equiv CF3CO2H to an ice-cold solution of 1.0 equiv of NaBH4 in THF and stirred for 1 h) was added dropwise and the resulting bright yellow mixture was stirred for 20 min at –78 °C. Neat 2,6-lutidine (970 µL, 8.3 mmol, 8.0 equiv) and chloroacetyl chloride (170 µL, 2.13 mmol, 2.0 equiv.) were then added sequentially. The reaction was warmed to 0 °C over 2 h and was then quenched by the dropwise addition of MeOH (~6 drops) followed by 30 mL of saturated aqueous NaHCO3. The contents were transferred to a separatory funnel with 30 mL of CH2Cl2, the organic layer was collected, and the aqueous phase was extracted with 3 x 50 mL of CH2Cl2. The combined organic fractions were dried over Na2SO4, filtered, and concentrated under reduced pressure to an orange oil. Purification of this material by chromatography on silica gel (20% EtOAc/hexanes) afforded SI-19 as a colorless oil (405 mg, 55%; yield varies between 49–55%). [α]D = +131.0 (c = 1.0, CHCl3)

TLC Rf = 0.58 in 40% EtOAc/hexanes 1H NMR (500 MHz, CDCl3) δ 6.06 (dt, J = 5.2, 1.8 Hz, 1H), 5.53 (d, J = 2.5 Hz, 1H), 4.96 (dt, J = 1.7 Hz; JSn-H = 7.1 Hz, 1H), 4.05-3.95 (m, 3H), 3.23 (s, 3H), 3.09 (d, J = 15.1 Hz, 1H), 2.99 (s, 3H), 2.89-2.80 (m, 1H), 2.66-2.52 (m, 2H), 2.30 (dd, J = 19.0, 8.3 Hz, 1H), 2.23 (ddd, J = 18.3, 4.4, 2.0 Hz, 1H), 2.17 (d, J = 13.8 Hz; JSn-H = 7.1 Hz, 1H), 1.93-1.70 (m, 9H), 1.57-1.41 (m, 6H), 1.34-1.26 (m, 6H), 0.90-0.84 (m, 15H), 0.65 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 217.0, 168.4, 147.7 (JSn-C = 17.5 Hz), 140.1, 124.2 (JSn-C = 21.0 Hz), 120.7, 97.9, 80.7, 79.1, 64.1, 50.9, 49.7, 41.3, 39.3, 38.4, 36.1, 35.33, 35.18, 33.6, 32.16, 32.02, 30.3, 29.33 (3C, JSn-C = 9.8 Hz), 27.7 (3C, JSn-C = 27.6 Hz), 19.5, 15.8, 13.9 (3C), 10.4 (3C, JSn-C = 158.5, 151.5 Hz) ppm. IR (thin film) ν 3314, 2956, 2926, 2852, 1735, 1642, 1481, 1437, 1410, 1376, 1347, 1255, 1196, 1146, 1088, 1077, 1010, 973, 949, 911 cm-1. HRMS (ESI+) calcd for C36H58ClNO5Sn 739.3025 found 740.3113 (M+H+).

MeO

Me

O

H

O

OH

Bu3Sn

MeN

SI-19

OCl

S21

SI-20. To a solution of chloroacetamide SI-19 (350 mg, 0.47 mmol) in 32 mL of 1:1 THF/benzene mixture were sequentially added solid NaOEt (64 mg, 0.95 mmol, 2.0 equiv) and 700 µL of absolute EtOH. The reaction mixture was stirred for 3 h then cooled to –40 °C in a dry ice/acetone bath. The reaction was quenched at this temperature by the sequential addition of 5 mL of 10% v/v AcOH in CH2Cl2 solution and 20 mL of saturated aqueous NH4Cl. The solution was warmed to room temperature in a water bath and was transferred to a separatory funnel with 30 mL of CH2Cl2. The organic layer was collected and the aqueous phase was extracted with 3 x 40 mL of CH2Cl2. The combined organic extracts were dried over Na2SO4, filtered, and concentrated under reduced pressure to a brown oil. Purification of this material by chromatography on silica gel (gradient elution: 50→60% EtOAc/hexanes) furnished SI-20 as a colorless oil (307 mg, 92%).

TLC Rf = 0.25 in 40% EtOAc/hexanes 1H NMR (500 MHz, CDCl3) δ 5.97 (ddd, J = 5.2, 2.2, 1.1 Hz, 1H), 4.78 (t, JSn-H = 7.4 Hz, 1H), 4.51 (d, J = 13.9 Hz, 1H), 4.02 (d, J = 13.9 Hz, 1H), 3.40 (d, J = 15.4 Hz, 1H), 3.26-3.23 (m, 4H), 2.99 (s, 3H), 2.87-2.75 (m, 1H), 2.56-2.43 (m, 3H), 2.30 (ddd, J = 18.9, 8.7, 1.2 Hz, 1H), 2.10 (dt, J = 13.6 Hz; JSn-H = 30.5 Hz, 1H), 2.05-1.91 (m, 4H), 1.88-1.72 (m, 5H), 1.50-1.44 (m, 6H), 1.31 (m, 6H), 0.92-0.85 (m, 15H), 0.76 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 216.3, 171.9, 146.0 (JSn-C = 17.4 Hz), 136.2, 124.5 (JSn-C = 21.2 Hz), 123.9, 97.5, 86.7, 81.0, 66.9, 60.3, 51.5, 49.7, 38.1, 36.6, 36.3, 36.0, 34.9, 33.7, 33.3, 31.8, 31.1, 29.3 (3C, JSn-C = 9.7 Hz), 27.7 (3C, JSn-C = 28.2 Hz), 19.8, 15.6, 13.9 (3C), 10.4 (3C, JSn-C = 158.5, 151.6 Hz) ppm. IR (thin film) ν 2956, 2926, 1741, 1673, 1490, 1464, 1400, 1365, 1337, 1256, 1195, 1146, 1089, 1052, 1009, 974 cm-1.

SI-21. To a –78 °C solution of ketone SI-20 (307 mg, 0.44 mmol) in 25 mL of THF was added a solution of KN(SiMe3)2 (0.5 M in THF, 1.31 mL, 0.66 mmol, 1.5 equiv) dropwise over 3 min via syringe. The resulting pale yellow mixture was stirred at –78 °C for 1 hour before a solution of PhNTf2 (235 mg, 0.66 mmol, 1.5 equiv) in 2 mL of THF was added via syringe. The reaction was warmed to 0 °C over 1 hour and quenched by the addition of 20 mL of saturated aqueous NaHCO3. The contents were transferred to a separatory funnel with 20 mL of CH2Cl2, and the mixture was extracted with 3 x 30 mL of CH2Cl2. The combined organic fractions were dried over Na2SO4, filtered, and concentrated under reduced pressure to a colorless oil. Purification of

MeOO

H

Me O

NMe

O

Bu3SnO

SI-20

MeOO

H

Me O

NMe

O

Bu3SnOTf

SI-21

S22

this material by chromatography on silica gel (gradient elution: 20→40% EtOAc/hexanes) gave SI-21 as a white crystalline solid (343 mg, 94%).

TLC Rf = 0.46 in 40% EtOAc/hexanes 1H NMR (400 MHz, CDCl3) δ 6.37 (d, J = 4.3 Hz, 1H), 5.68 (dd, J = 3.1, 2.1 Hz, 1H), 5.16 (t, JSn-H = 7.8 Hz, 1H), 4.44 (d, J = 17.0 Hz, 1H), 4.28 (d, J = 17.1 Hz, 1H), 3.68 (d, J = 14.6 Hz, 1H), 3.59 (dd, J = 17.8, 2.0 Hz, 1H), 3.27 (s, 3H), 3.03 (s, 3H), 2.92 (d, J = 14.6 Hz, 1H), 2.50 (ddd, J = 14.8, 11.7, 3.1 Hz, 1H), 2.43-2.33 (m, 2H), 2.18-2.03 (dt, J = 13.3 Hz; JSn-H = 30.5 Hz, 1H), 2.00-1.91 (m, 4H), 1.84-1.74 (m, 3H), 1.56-1.47 (m, 7H), 1.33 (m, 6H), 0.94-0.89 (m, 15H), 0.71 (s, 3H) ppm. 13C NMR (100 MHz, CDCl3) δ 170.8, 148.2, 142.9 (JSn-C = 17.4 Hz), 136.3, 125.4, 122.8 (JSn-C = 18.6 Hz), 119.9, 117.3, 113.0, 98.2, 81.0, 80.0, 67.0, 58.6, 49.9, 49.5, 38.0, 37.5, 35.6, 35.2, 33.5, 31.7, 30.8, 29.3 (3C, JSn-C = 9.7 Hz), 27.7 (3C, JSn-C = 28.7 Hz), 19.6, 15.6, 13.9 (3C), 10.5 (3C, JSn-C = 158.2, 151.3 Hz) ppm. IR (thin film) ν 2957, 2926, 1652, 1491, 1426, 1377, 1339, 1248, 1215, 1143, 1090, 1052, 1027, 976, 952 cm-1. HRMS (ESI+) calcd for C37H56F3NO7SSn 835.2752 found 836.2839 (M+H+).

SI-22. Allylic stannane SI-21 (116 mg, 0.14 mmol) and CuCl2 (62 mg, 0.46 mmol, 3.3 equiv) were dissolved in 13 mL of 1,4-dioxane, which had been sparged with O2 for 5 min immediately prior to use. The reaction vessel was sealed with a polyethylene stopper and the contents were stirred at 73 °C. After 15 h, the reaction was cooled to room temperature and the green solution was transferred to a separatory funnel with 20 mL of H2O and 30 mL of CH2Cl2. The organic layer was collected and the aqueous phase was extracted with 3 x 30 mL of CH2Cl2. The combined organic fractions were dried over Na2SO4, filtered, and concentrated under reduced pressure to a colorless oil. Purification of this material by chromatography on silica gel (gradient elution: 50→60% EtOAc/hexanes) afforded SI-22 as a colorless oil (69 mg, 89%).

[α]D = −5.5 (c = 1.0, CHCl3) TLC Rf = 0.25 in 70% EtOAc/hexanes 1H NMR (500 MHz, CDCl3) δ 9.99 (s, 1H), 6.43 (d, J = 3.8 Hz, 1H), 6.20 (s, 1H), 5.78 (dd, J = 3.2, 2.0 Hz, 1H), 4.45 (d, J = 17.0 Hz, 1H), 4.26 (d, J = 17.0 Hz, 1H), 3.72 (d, J = 14.7 Hz, 1H), 3.55 (dd, J = 18.1, 1.8 Hz, 1H), 3.29 (s, 3H), 3.12 (d, J = 14.8 Hz, 1H), 3.03 (s, 3H), 2.46-2.40 (m, 2H), 2.07 (ddd, J = 18.6, 5.2, 1.7 Hz, 1H), 2.05-1.80 (m, 4H), 1.76 (dt, J = 13.2, 4.6 Hz, 1H), 1.71-1.63 (m, 2H), 0.61 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 193.7, 170.4, 147.1, 146.0, 141.4, 140.8, 134.3, 133.3, 127.3, 125.8, 124.5, 122.4, 119.9, 117.3, 115.2, 98.7, 81.1, 78.7, 67.0, 62.4, 58.5, 50.2, 48.1, 37.7, 37.2, 35.7, 35.4, 35.2, 33.6, 33.3, 33.2, 31.7, 31.5, 31.3, 30.8, 19.8, 19.3 ppm.

MeOO

H

MeOHC

O

NMe

O OTf

SI-22

S23

Note: additional peaks in the 13C and 1H NMR spectra may result from rotameric isomers or partial hydrate formation. Further studies to elucidate the identity of the minor component were not conducted. IR (thin film) ν 3447, 2960, 1700, 1648, 1453, 1347, 1248, 1217, 1175, 1140, 1094, 1054, 1028, 979, 910, 871 cm-1. HRMS (ESI+) calcd for C25H28F3NO8S 559.1488 found 560.1558 (M+H+).

SI-23. To a solution of enal SI-22 (105 mg, 0.19 mmol) in 10 mL of DMSO were added 2.6 mL of an aqueous solution of NaClO2 (400 mg, 4.42 mmol, 24 equiv) and NaH2PO4 (421 mg, 3.51 mmol, 19 equiv) followed immediately by an additional 2.6 mL of H2O. The mixture immediately turned yellow and a significant exotherm was measured. The reaction was stirred for 3 hours during which time the yellow color typically faded. The mixture was diluted with 25 mL of EtOAc and transferred to a separtory funnel containing 40 mL of 5% aqueous LiCl solution. The organic layer was collected and the aqueous phase was extracted with 2 x 30 mL of EtOAc. The combined organic fractions were sequentially washed with 20 mL of 5% aqueous LiCl and 20 mL of saturated aqueous NaCl, dried over MgSO4, filtered, and concentrated under reduced pressure to a colorless oil. The unpurified product was dissolved in 10 mL of CH2Cl2, the solution was cooled to 0 °C, and pyridine (300 µL, 3.72 mmol, 20 equiv) and SOCl2 (90 µL, 1.24 mmol, 6.5 equiv) were added sequentially. The reaction mixture was allowed to warm to room temperature over 30 min, diluted with 3 mL of toluene, and concentrated under reduced pressure to a brown semi-solid. The unpurified acid chloride was then dissolved in 10 mL of acetone and to this solution was added 1.5 mL of an aqueous solution of NaN3 (50 mg, 0.77 mmol, 4 equiv). The mixture was stirred for 3 h, then transferred to a separatory funnel with 30 mL of CH2Cl2 and 30 mL of H2O. The organic layer was collected and the aqueous phase was extracted with 3 x 20 mL of CH2Cl2. The combined organic extracts were dried over Na2SO4, filtered, and concentrated under reduced pressure to a brown oil. This material was dissolved in 2 mL of EtOAc and filtered through a plug of silica gel using EtOAc as the eluent. The filtrate was concentrated under reduced pressure. The isolated product was then dissolved in 3 mL of a 1:1 1,4-dioxane/H2O solution to which 600 µL of AcOH was added. The mixture was stirred at 90 °C for 15 h. Following this time, the reaction was cooled to room temperature and the solution transferred to a separatory funnel containing 10 mL saturated aqueous NaHCO3 with 15 mL of CH2Cl2. The organic layer was collected and the aqueous phase was extracted with 3 x 10 mL of CH2Cl2. The combined organic fractions were dried over Na2SO4, filtered, and concentrated under reduced pressure to a colorless oil. Purification of this material by chromatography on silica gel (gradient elution: 50→60% EtOAc/hexanes) afforded SI-23 as a colorless crystalline solid (58 mg, 57% over 4 steps).

[α]D = −50.4 (c = 0.5, CHCl3) TLC Rf = 0.25 in 70% EtOAc/hexanes

HOO

H

MeO

O

NMe

O OTf

SI-23

S24

1H NMR (400 MHz, CDCl3) δ 6.34 (dd, J = 5.1, 2.3 Hz, 1H), 5.82 (t, J = 2.4 Hz, 1H), 4.43 (d, J = 17.9 Hz, 1H), 4.22 (d, J = 17.9 Hz, 1H), 4.06 (d, J = 12.0 Hz, 1H), 3.51 (d, J = 19.2 Hz, 1H), 3.01 (s, 3H), 2.83 (s, 1H), 2.58 (s, 1H), 2.53-2.40 (m, 3H), 2.24-2.13 (m, 2H), 2.06 (ddd, J = 19.2, 4.8, 1.5 Hz, 1H), 1.94 (td, J = 11.3, 5.4 Hz, 1H), 1.90-1.82 (m, 2H), 1.78 (td, J = 12.3, 11.6, 3.1 Hz, 1H), 1.43-1.35 (m, 2H), 0.86 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 205.8, 170.3, 145.9, 137.4, 124.9, 119.9, 117.3, 115.7, 95.4, 82.5, 81.9, 66.0, 59.9, 50.3, 46.3, 39.9, 38.0, 35.2, 33.0, 32.4, 31.1, 30.1, 22.0 ppm. IR (thin film) ν 3371, 2937, 1727, 1636, 1424, 1357, 1216,1140, 1098, 1028, 1016, 862 cm-1.

HRMS (ESI+) calcd for C23H26F3NO8S 533.1331 found 534.1398 (M+H +).

SI-24. Hemiketal SI-23 (54 mg, 98 µmol) was dissolved in 5.0 mL of anhydrous benzene. To this solution were added sequentially 300 mg of freshly activated powdered 4 Å molecular sieves, 4-methoxyphenethyl alcohol (150 µL, 230 mg, 1.51 mmol, 15.0 equiv), and p-TsOH (5 mg, 29 µmol, 0.3 equiv, azeotropically dried with 3 x 2 mL anhydrous toluene prior to use). The suspension was stirred 3 h following which time 1.0 mL of Et3N was added. The mixture was filtered through a small pad of Celite, and the flask and filter cake were rinsed with 10 mL of CH2Cl2. The combined filtrate was concentrated under reduced pressure to a colorless oil. Purification of this material by chromatography on silica gel (gradient elution: 40→70% EtOAc/hexanes) gave SI-24 (59 mg, 89%) as a colorless oil. TLC Rf = 0.35 in 60% EtOAc/hexanes 1H NMR (500 MHz, CDCl3) δ 7.11 (d, J = 8.5 Hz, 2H), 6.82 (d, J = 8.6 Hz, 2H), 6.33 (dd, J = 4.9, 2.3 Hz, 1H), 5.79 (s, 1H), 4.45 (d, J = 17.7 Hz, 1H), 4.25 (d, J = 17.8 Hz, 1H), 3.98 (d, J = 14.0 Hz, 1H), 3.80 (s, 3H), 3.70 (t, J = 7.2 Hz, 2H), 3.40 (d, J = 19.3 Hz, 1H), 3.04 (s, 3H), 2.98-2.94 (m, 1H), 2.77 (td, J = 7.0, 2.9 Hz, 2H), 2.55-2.48 (m, 2H), 2.40 (dd, J = 19.1, 1.8 Hz, 1H), 2.25-2.16 (m, 2H), 2.07 (ddd, J = 19.3, 4.5, 1.7 Hz, 1H), 2.01-1.90 (m, 2H), 1.88-1.85 (m, 1H), 1.62-1.55 (m, 2H), 1.38 (td, J = 13.1, 4.4 Hz, 1H), 0.87 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 205.3, 170.2, 158.3, 145.9, 137.4, 131.3, 130.2 (2C), 124.9, 122.5, 119.9, 117.3, 115.6, 113.9 (2C), 98.1, 81.9, 66.1, 63.8, 59.7, 55.5, 50.3, 46.3, 38.0, 37.2, 35.9, 35.1, 32.3, 31.2, 30.5, 29.7, 21.9 ppm. IR (thin film) ν 2938, 1729, 1653, 1613, 1513, 1465, 1424, 1359, 1329, 1301, 1248, 1174, 1141, 1114, 1097, 1019, 989, 957, 917 cm-1.

OO

H

MeO

O

NMe

O OTf


S25

SI-25. In an intert-atmosphere N2 glove box, a 10 mL round bottom flask containing vinyl triflate SI-24 (54 mg, 81 µmol) was charged with Pd(PPh3)4 (9 mg, 7.8 µmol, 0.1 equiv), CuCl (40 mg, 0.4 mmol, 5.0 equiv), and LiCl (20 mg, 0.48 mmol, 6.0 equiv). The flask was sealed with a rubber septum, removed from the glove box, and fitted with a N2 inlet. Degassed THF (5 mL, freeze-pump thawed 3x) and tributyl(1-ethoxyvinyl)tin (35 µL, 100 µmol, 1.3 equiv.) were added sequentially and the mixture was stirred at 60 °C for 3 h. Following this time, the dark brown solution was cooled to 0 °C and 5 mL of 1.0 M aqueous oxalic acid was added dropwise over 2 min. The mixture was stirred vigorously for 20 min before 5 mL of saturated aqueous NaHCO3 was slowly added. The contents were transferred to a separatory funnel with 10 mL of CH2Cl2, the organic layer was collected, and the aqueous layer was extracted with 3 x 10 mL of CH2Cl2. The organic fractions were combined, dried over Na2SO4, filtered, and concentrated under reduced pressure to a dark brown oily residue. Purification of this material by chromatography on silica gel (33% THF/toluene) furnished SI-25 (35 mg, 77%) as a colorless oil.

[α]D = −9.7 (c = 0.5, CHCl3) TLC Rf = 0.38 in 90% EtOAc/hexanes 1H NMR (600 MHz, CDCl3) δ 7.10 (d, J = 8.6 Hz, 2H), 6.86 (s, 1H), 6.81 (d, J = 8.6 Hz, 2H), 6.28 (dd, J = 5.1, 2.4 Hz, 1H), 4.36 (d, J = 17.8 Hz, 1H), 4.03-3.98 (m, 2H), 3.80-3.76 (m, 3H), 3.68-3.61 (m, 4H), 3.36-3.34 (m, 1H), 2.85 (s, 3H), 2.80-2.72 (m, 2H), 2.66 (d, J = 12.7 Hz, 1H), 2.49 (ddd, J = 18.9, 4.7, 2.2 Hz, 1H), 2.42 (d, J = 22.1 Hz, 1H), 2.26 (s, 3H), 2.18 (d, J = 12.8 Hz, 1H), 2.10-2.00 (m, 2H), 1.92-1.82 (m, 2H), 1.67-1.56 (m, 2H), 1.33 (ddd, J = 13.6, 12.4, 4.2 Hz, 1H), 0.84 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 207.4, 195.7, 170.5, 158.3, 146.3, 143.4, 137.8, 131.3, 130.2, 123.8, 113.9, 104.1, 98.2, 85.0, 82.1, 67.5, 67.3, 66.2, 63.7, 63.0 61.1, 55.5, 51.0, 47.8, 38.8, 37.6, 37.1, 37.0, 35.9, 35.1, 32.6, 32.2, 31.1, 30.8, 30.4, 29.7, 27.7, 26.9, 23.7, 22.2 ppm. Note: additional peaks (13C) and broadening (1H, 13C) of the NMR spectra likely results from rotameric isomers about the C/D/E-ring propellane core. IR (thin film) ν 2933, 1725, 1669, 1646, 1513, 1349, 1246, 996 cm-1.

HRMS (ESI+) calcd for C33H39NO7 561.2727 found 562.2801 (M+H+).

OO

H

MeO

O

NMe

O O Me


S26

SI-26. A 0.4 M solution of AlH3 in THF was prepared according to reference 39: A 25 mL round bottom flask containing a stir bar was charged with solid, anhydrous AlCl3 (144 mg, 1.08 mmol, 1 equiv) in a N2 glove box. The flask was sealed with a rubber septum, removed from the glove box, and fitted with a N2 inlet. The flask was cooled to 0 °C with stirring. To the ice cold flask was then dropwise added 7.4 mL of THF and the mixture was stirred until all of the AlCl3 dissolved. To the ice cold solution was added dropwise a solution LiAlH4 (1M in THF, 3.3 mL, 3 equiv). The reaction mixture was warmed to room temperature and stirred for 20 min prior to use. A freshly prepared solution of AlH3 (0.4 M in THF, 450 µL, 0.18 mmol, 8.5 equiv) was added dropwise via syringe to a –78 °C solution of tricarbonyl SI-25 (12 mg, 21 µmol) in 3.0 mL of THF. The solution was warmed to 0 °C over 2 h and the reaction was then quenched by the slow addition of excess powdered Na2SO410H2O (~300 mg). Gas evolution was observed upon addition of the salt. The suspension was stirred vigorously at room temperature for 4 h, after which time the solution was dried by the addition of excess MgSO4, and filtered through a small pad of Celite. The flask and filter cake were rinsed with 30 mL of CH2Cl2. The combined filtrates were concentrated under reduced pressure to a colorless residue. This material was purified by reverse-phase HPLC (Silicycle SiliaChrom Aq C18, 5 µm, 10 x 250 mm column, eluting with a gradient flow over 60 min of 25:75 MeCN (with 0.5% AcOH)/0.5% aqueous AcOH→45:55 MeCN (with 0.5% AcOH)/0.5% aqueous AcOH, 2-fraction/min time-slice collection, 214 and 254 nm UV detection). At a flow rate of 4 mL/min, the desired compound had a retention time of ~13 min (typically fractions 26-30) and the isolation procedure was as follows: individual fractions were made basic with 1.5 mL of 1.0 M aqueous NH4OH, extracted with 4 x 2 mL of CHCl3, dried over Na2SO4, filtered, and concentrated under reduced pressure. Each fraction was analyzed by 1H NMR; those containing the desired product were combined and concentrated under reduced pressure to afford SI-26 as a colorless oil (3.9 mg, 33%).

TLC Rf = 0.48 in 12.5% MeOH/CHCl3 1H NMR (500 MHz, CDCl3) δ 7.12 (d, J = 8.7 Hz, 2H), 6.83 (d, J = 8.7 Hz, 2H), 6.21 (dd, J = 5.6, 2.1 Hz, 1H), 5.66 (s, 1H), 4.46 (q, J = 6.4 Hz, 1H), 4.02 (t, J = 11.0 Hz, 1H), 3.82-3.80 (m, 4H), 3.74 (dt, J = 9.0, 7.4 Hz, 1H), 3.64 (ddd, J = 9.0, 7.4, 6.5 Hz, 1H), 3.57 (d, J = 13.4 Hz, 1H), 3.10 (d, J = 18.1 Hz, 1H), 2.81-2.65 (m, 5H), 2.44 (ddd, J = 18.6, 4.3, 2.2 Hz, 1H), 2.40-2.28 (m, 6H), 2.14-2.09 (m, 1H), 1.94-1.87 (m, 2H), 1.78-1.69 (m, 4H), 1.65 (td, J = 12.4, 4.6 Hz, 1H), 1.43 (d, J = 6.4 Hz, 3H), 1.37 (ddd, J = 13.6, 12.1, 5.1 Hz, 1H), 0.85 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 158.0, 152.3, 140.6, 131.0, 129.8 (2C), 126.9, 124.5, 113.6 (2C), 98.4, 87.8, 77.7, 66.6, 66.5, 63.19, 63.18, 62.1, 59.8, 59.7, 55.4, 47.3, 47.1, 40.6, 36.3, 35.8, 32.2, 31.5, 31.3, 31.03, 31.00, 24.2, 19.5 ppm. IR (thin film) ν 3391, 2931, 1612, 1513, 1456, 1300, 1247, 1147, 1102, 1035, 966, 929 cm-1.

LRMS (ES+) calcd for C33H45NO6 551.3 found 552.2 (M+H+).

OO

H

MeHO

O

NMe


OHMe

S27

(−)-Batrachotoxinin A. To a solution of SI-26 (3.9 mg, 7.0 µmol) in 1.0 mL of a 3:2 acetone/H2O solution was added p-TsOHH2O (15 mg, 87 µmol, 12 equiv). The reaction was stirred for 14 h then quenched by the addition of 2 mL of 1 M aqueous NH4OH and 3 mL of CHCl3. The organic layer was collected and the aqueous layer was extracted with 4 x 3 mL CHCl3. The combined organic fractions were dried over Na2SO4, filtered, and concentrated under reduced pressure to an oily residue. Purification of this material by chromatography on NH4OH pre-treated silica gel (gradient elution: 40% EtOAc/hexanes→ EtOAc with 0.5% v/v Et3N) afforded (−)-batrachotoxinin A as a white solid (2.4 mg, 83%). The 1H NMR spectrum of synthetic batrachotoxinin A matched spectral data generously provided by Professor Y. Kishi (see S64). [α]D = −36.1 (c = 0.1, MeOH); Lit. (see reference 53): [α]D = −42 (c = 0.45, MeOH)

TLC Rf = 0.28 in 10% MeOH/CHCl3 1H NMR (600 MHz, CDCl3) δ 6.24 (d, J = 4.5 Hz, 1H), 5.66 (t, J = 2.4 Hz, 1H), 4.46 (q, J = 6.6 Hz, 1H), 4.07 (t, J = 11.3 Hz, 1H), 3.76 (t, J = 7.0 Hz, 1H), 3.55 (ddd, J = 13.4, 4.1, 2.7 Hz, 1H), 3.17 (d, J = 18.3 Hz, 1H), 2.71-2.58 (m, 4H), 2.48-2.41 (m, 3H), 2.36-2.30 (m, 5H), 2.13 (m, 2H), 1.90 (ddd, J = 18.6, 5.5, 1.6 Hz, 1H), 1.84-1.72 (m, 3H), 1.65 (tt, J = 12.5, 4.6 Hz, 1H), 1.49 (ddd, J = 13.0, 5.6, 4.0 Hz, 1H), 1.40-1.35 (m, 4H), 0.87 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 152.8, 140.8, 127.2, 124.8, 95.7, 87.7, 78.4, 66.9, 66.8, 62.8, 61.8, 59.5, 58.1, 47.7, 46.9, 41.5, 40.3, 36.4, 32.6, 32.4, 32.0, 30.6, 24.5, 19.2 ppm.

IR (thin film) ν 3285, 2927, 1453, 1341, 1303, 1264, 1156, 1101, 1076, 1049, 1016, 995, 968, 929, 879 cm-1. HRMS (ESI+) calcd for C24H35NO5 417.2515 found 418.2585 (M+H+).

(+)-Batrachotoxinin A. This compound was prepared from ent-SI-5 and ent-SI-11 following the same sequence of steps used to prepare (−)-batrachotoxinin A from SI-5 and SI-11. TLC and 1H NMR were identical to those reported for (−)-batrachotoxinin A.

[α]D = +38.4 (c = 0.1, MeOH)

(−)-Batrachotoxinin A

HOO

H

MeHO

O

NMe

OHMe

(+)-Batrachotoxinin A

OHO

H

MeOH

O

NMe

HOMe

S28

SI-27. (Ethyl carbonic)-2,4-dimethyl-1H-pyrrole-3-carboxylic anhydride. This compound was prepared as described in reference 10.

(−)-Batrachotoxin. To a solution of (−)-batrachotoxinin A (2.0 mg, 4.8 µmol) in 2.0 mL of anhydrous benzene were sequentially added Et3N (150 µL, 1.1 mmol, 229 equiv) and SI-27 (10 mg, 47.3 µmol, 9.8 equiv). The reaction mixture was stirred at 45 °C for 18 h. Following this time, all volatiles were removed under reduced pressure to give a pale yellow residue. This material was transferred to a 16x125 mm test tube with 4 mL of CHCl3. The solution was cooled in an ice bath and 4.0 mL of ice-cold 0.1 M aqueous HCl was added. With the aid of a glass pipet, the layers were mixed, the CHCl3 layer was carefully removed, and the aqueous layer was extracted once more with 4.0 mL of CHCl3. The combined organic fractions were discarded. The aqueous layer was then basified to pH 10 with 2 mL of 1 M aqueous NH4OH and the solution was extracted with 3 x 4 mL of CHCl3. The combined organic layers were dried over Na2SO4, filtered, and concentrated under reduced pressure to a colorless residue. Purification of this material by chromatography on NH4OH pre-treated silica gel (gradient elution: 60% EtOAc/pentane→80% EtOAc/pentane with 0.5% v/v Et3N) afforded (−)-batrachotoxin as a white solid (2.0 mg, 79%). This synthetic batrachotoxin co-eluted with an authentic sample of batrachotoxin on reverse-phase HPLC (see S69−70 for details).

TLC Rf = 0.33 in 10% MeOH/CHCl3 1H NMR (600 MHz, CDCl3) δ 7.83 (s, 1H), 6.34 (dd, J = 2.4, 1.2 Hz, 1H), 6.16 (d, J = 4.4 Hz, 1H), 5.87 (q, J = 6.4 Hz, 1H), 5.84 (s, 1H), 3.71-3.64 (m, 2H), 3.53 (ddd, J = 13.5, 9.3, 4.1 Hz, 1H), 3.16 (d, J = 17.7 Hz, 1H), 2.94-2.90 (m, 1H), 2.77 (d, J = 14.0 Hz, 1H), 2.65 (d, J = 14.0 Hz, 1H), 2.56-2.51 (m, 1H), 2.50 (s, 3H), 2.46-2.40 (m, 4H), 2.35-2.32 (m, 1H), 2.25 (s, 3H), 2.19-2.13 (m, 2H), 2.09 (d, J = 10.4 Hz, 1H), 1.93-1.89 (m, 2H), 1.79-1.68 (m, 3H), 1.65-1.59 (m, 1H), 1.50 (d, J = 6.4 Hz, 3H), 1.46 (ddd, J = 13.0, 5.6, 3.9 Hz, 1H), 1.33 (td, J = 12.9, 5.1 Hz, 1H), 0.88 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 165.7, 151.5, 140.6, 136.0, 125.5, 125.2, 122.0, 114.3, 111.3, 95.9, 89.4, 79.7, 67.6, 65.7, 63.2, 59.6, 58.8, 57.5, 49.3, 47.4, 40.8, 40.8, 37.2, 33.0, 32.9, 32.9, 31.0, 20.2, 19.6, 14.6, 12.5 ppm. IR (thin film) ν 3301, 2927, 1665, 1439, 1342, 1257, 1083, 1048, 991, 965 cm-1.

HRMS (ESI+) calcd for C31H42N2O6 538.3043 found 539.3120 (M+H+).

EtO O

O O

NH

Me

Me

SI-27

(–)-Batrachotoxin

HOO

H

MeHO

O

NMe

OMe

O

NH

Me

Me

S29

(+)-Batrachotoxin. This compound was prepared from (+)-batrachotoxinin A following the same sequence of steps used to prepare (−)-batrachotoxin from (−)-batrachotoxinin A. TLC and 1H NMR were identical to those reported for (−)-batrachotoxin. [α]D = +25.1 (c = 0.1, MeOH)

Batrachotoxinin A 20-(R)-benzoate. To a stirred solution of (−)-batrachotoxinin A (2.4 mg, 5.7 µmol) in 1.5 mL of anhydrous benzene were added sequentially Et3N (100 µL, 0.718 mmol, 126 equiv) and benzoic(ethylcarbonic)anhydride (13 mg, 68 µmol, 12 equiv). The reaction mixture was stirred 45 °C until TLC (80% EtOAc/hexanes with 1% v/v Et3N) indicated complete consumption of the starting material. All volatiles were then removed under reduced pressure. Purification of the isolated material by chromatography on NH4OH pre-treated silica gel (gradient elution: 30→70% EtOAc/hexanes with 1% v/v Et3N) furnished (−)-batrachotoxinin A 20-(R)-benzoate as a white solid (2.1 mg, 70%).

[α]D = −86.7 (c = 0.2, MeOH) TLC Rf = 0.2 in 80% EtOAc/hexanes with 1% v/v Et3N 1H NMR (600 MHz, CDCl3) δ 8.07 (dd, J = 8.4, 1.3 Hz, 2H), 7.55 (tt, J = 7.4, 1.5 Hz, 1H), 7.44 (t, J = 7.6 Hz, 2H), 6.17 (dd, J = 4.3, 1.0 Hz, 1H), 5.95-5.91 (m, 2H), 3.68-3.63 (m, 2H), 3.53 (ddd, J = 13.3, 9.1, 4.2 Hz, 1H), 3.23 (d, J = 17.6 Hz, 1H), 2.95-2.91 (m, 1H), 2.79 (d, J = 14.1 Hz, 1H), 2.60-2.51 (m, 2H), 2.43 (ddd, J = 18.6, 4.6, 2.2 Hz, 1H), 2.38-2.33 (m, 4H), 2.18-2.15 (m, 2H), 2.09 (dd, J = 13.8, 10.6 Hz, 1H), 2.02 (dd, J = 13.8, 11.1 Hz, 1H), 1.91 (ddd, J = 18.9, 5.5, 1.4 Hz, 1H), 1.80 (td, J = 12.6, 4.0 Hz, 1H), 1.77-1.71 (m, 1H), 1.67-1.61 (m, 2H), 1.55 (d, J = 6.4 Hz, 3H), 1.48 (m, 1H), 1.36-1.32 (m, 1H), 0.87 (s, 3H) ppm. 13C NMR (125 MHz, CDCl3) δ 166.0, 150.0, 140.2, 132.8, 130.7, 129.7 (2C), 128.3 (2C), 126.3, 125.0, 95.8, 89.0, 79.4, 68.1, 67.5, 63.0, 59.4, 58.5, 57.0, 49.0, 47.2, 40.6, 40.2, 37.0, 32.8, 32.7, 32.6, 30.8, 19.3, 19.1 ppm. IR (thin film) ν 3271, 2925, 1711, 1451, 1248, 1027 cm-1.

HRMS (ESI+) calcd for C31H39NO6 521.2777 found 522.2848 (M+H+).

(+)-Batrachotoxin

OHO

H

MeOH

O

NMe

OMe

O

HN

Me

Me

(−)-Batrachotoxinin A 20-(R)-benzoate

HOO

H

MeHO

O

NMe

OMe

O

S30

ent-Batrachotoxinin A 20-(R)-benzoate. This compound was prepared from (+)-batrachotoxinin A following the same sequence of steps used to prepare (–)-batrachotoxinin A 20-(R)-benzoate from (−)-batrachotoxinin A. TLC and 1H NMR were identical to those reported for (−)-batrachotoxinin A 20-(R)-benzoate.

[α]D = +80.4 (c = 0.2, MeOH)

(+)-Batrachotoxin A 20-(R)-benzoate

OHO

H

MeOH

O

NMe

OMe

O

S31

1H and 13C NMR spectra

TBSO

HO O

SI-2

S32

TBSO

I O

SI-3

S33

TBSO

HO

SI-4

S34

TBSO

O

SI-5

S35

Me

H

O

O

O

SI-7

S36

Me

H

O

O

OTES

SI-8

S37

Me

H

O

O

BrO

SI-9

S38

Me

H

Br

TMS

OH

O

O

SI-10

S39

MeO

Me

O

H

TMS

Br

SI-11

S40

MeO

Me

O

H

OTBS

OH

TMS

SI-12

S41

MeO

Me

O

H

OTBS

OH

SI-13

S42

MeO

Me

O

H

OTBS

OH

HSnBu3

7

S43

Position 1H δ (ppm) nOe H11’ 6.17 H1, 1.81 H2, 1.76

NOE

MeO

Me

O

H

OTBS

OH

HSnBu3

7

MeO

Me

O

H

H

OH

SnBu3 OSitBuMe211'

12

7

S44

MeO

Me

O

H

OTBS

OH

MeSnBu3

8

S45

Position 1H δ (ppm) nOe H11’ 6.86 H1, 2.5

MeO

Me

O

H

OTBS

OH

MeSnBu3

NOE

8

MeO

Me

O

H

Me

OH

SnBu3 OSitBuMe211'

12

8

S46

MeO

Me

O

H

OTBS

OSiEt2

TMS

SI-15

S47

MeO

Me

O

H

OBu3Sn

OTBSEt2SiH

TMS

SI-16

S48

COSY; 500 MHz, CDCl3

HSQC; 500 MHz, CDCl3

S49

Position 1H NMR (500 MHz, CDCl3) 13C NMR (125 MHz, CDCl3) 7 6.11 (dd, J = 3.5, 1.2 Hz, 1H) 121.2 8 - 141.6 9 - 89.5 10 - 35.3 11 - 142.8 12 5.51 (s, 1H) 134.7 13 - 65.3 14 - 80.1 17 4.00 (t, J = 7.7 Hz, 1H) 85.0 18 - 164.1

11' 2.14 (d, J = 14.1 Hz, 1H), 2.0 (d, J = 14.3 Hz, 1H) 15.3

18' 6.24 (s, 1H) 142.8 Relevant HMBC’s for allylstannane assignment: H11’ → C12 C11’ → H12 H12 → C9, C11, C13, C14, C17 C12 → H11’, H17

HMBC; 500 MHz, CDCl3

MeO

Me

O

H


SI-16

HMe3Si

1818'

17

16

1514

13

1211

11'

12

34 6

7

89

S50

Position 1H δ (ppm) nOe H12 5.51 H18', 6.24 H17, 4.00

1D nOe; 500 MHz, CDCl3

MeO

Me

O

H


SI-16

HMe3Si 18'

1712

S51

Fig. S5 1H NMR spectrum from the radical cyclization of SI-15 with Bu3SnD, Et3B, and O2 provides support for a radical cyclization cascade mechanism involving a 1,4-hydrogen atom transfer. (A) Comparison of the full deuterium-labeled 1H NMR spectrum (top) with that for SI-16 (bottom) reveals that deuterium was not incorporated into the vinyl silane C–H (6.24 ppm). (B) Expanded view of the 1H NMR spectra from the deuterium labeling study (top) and SI-16 (bottom) shows the absence of an allylic C-H signal (d, 2.15 ppm) in the top spectrum. Deuterium incorporation at the allylic position supports the proposed mechanism.

MeO

Me

O

H

OBu3Sn

OTBSEt2Si H

TMS

D H

MeO

Me

O

H

OBu3Sn

OTBSEt2Si H

TMS

H H

-0.50.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.0f1 (ppm)

1

2

MeO

Me

O

H

OBu3Sn

OTBSEt2Si H

TMS

D H

MeO

Me

O

H

OBu3Sn

OTBSEt2Si H

TMS

H H

1.551.601.651.701.751.801.851.901.952.002.052.102.152.202.252.302.352.402.452.50f1 (ppm)

1

2

A

B

S52

MeO

Me

O

H

Bu3Sn

OH

OH

TMS

SI-17

S53

MeO

Me

O

H

OHC O

OH

Bu3Sn

SI-18

S54

MeO

Me

O

H

O

OH

Bu3Sn

N

OCl Me

SI-19

S55

MeOO

H

Me O

NMe

O

Bu3Sn

O

SI-20

S56

MeOO

H

Me O

NMe

O

Bu3Sn

OTf

SI-21

S57

MeOO

H

MeOHC

O

NMe

OOTf

SI-22

S58

HOO

H

MeO

O

NMe

OOTf

SI-23

S59

OO

H

MeO

O

NMe

OOTf

PMB

SI-24

S60

OO

H

MeO

O

NMe

O O Me

PMB

SI-25

S61

OO

H

MeHO

O

NMe

PMB

MeOH

SI-26


S62



S63

HOO

H

MeHO

O

NMe

OHMe

batrachotoxinin A

S64

1H NMR spectra of synthetic and natural batrachotoxinin A from Y. Kishi (17)

S65

HOO

H

MeHO

O

NMe

OMe

batrachotoxin

O

NH

Me

Me


S66



S67

HOO

H

MeHO

O

NMe

OMe

O

batrachotoxinin A 20α−benzoate


S68


S69

HPLC Data for natural and synthetic batrachotoxin Acquisition parameters: Flow rate: 1.5 mL/min Gradient: 10:90 MeCN (with 1% AcOH)/1% aqueous AcOH à 50:50 MeCN (with 1% AcOH)/1% aqueous AcOH over 15 min Eclipse XDB-C18 column (5 µm, 4.6 x 150 mm), 22 °C 260 nm detection Synthetic BTX

Natural BTX

=====================================================================Acq. Operator : SYSTEM Seq. Line : 7Acq. Instrument : HPLC 1 Location : Vial 92Injection Date : 2/19/2015 8:21:20 PM Inj : 1 Inj Volume : 5.000 µlAcq. Method : C:\CHEM32\1\DATA\DEF_LC 2015-02-19 15-29-29\MML_BTX.MLast changed : 2/19/2015 3:29:29 PM by SYSTEMAnalysis Method : C:\CHEM32\1\DATA\DEF_LC 2015-02-19 15-29-29\MML_BTX.M (Sequence Method)Last changed : 2/19/2015 9:40:33 PM by SYSTEM (modified after loading)

min2 4 6 8 10 12 14

mAU

0

20

40

60

80

100

120

140

160

DAD1 G, Sig=260,8 Ref=off (DEF_LC 2015-02-19 15-29-29\092-0701.D)

5.9

00

7.5

53

10.

406

11.

468

===================================================================== Area Percent Report ===================================================================== Sorted By : SignalMultiplier : 1.0000Dilution : 1.0000Use Multiplier & Dilution Factor with ISTDs Signal 1: DAD1 G, Sig=260,8 Ref=off Peak RetTime Type Width Area Height Area # [min] [min] [mAU*s] [mAU] %----|-------|----|-------|----------|----------|--------| 1 5.900 VV 0.0730 9.26650 1.96554 0.5134 2 7.553 VB 0.1558 1594.76160 155.24301 88.3516 3 10.406 BB 0.3408 179.46155 7.73093 9.9424 4 11.468 BB 0.0837 21.52795 3.82514 1.1927 Totals : 1805.01759 168.76461

Data File C:\CHEM32\1\DATA\DEF_LC 2015-02-19 15-29-29\092-0701.DSample Name: synth btx 2

HPLC 1 2/19/2015 9:41:29 PM SYSTEM Page 1 of 2

=====================================================================Acq. Operator : SYSTEM Seq. Line : 3Acq. Instrument : HPLC 1 Location : Vial 92Injection Date : 2/19/2015 5:27:30 PM Inj : 1 Inj Volume : 5.000 µlMethod : C:\CHEM32\1\DATA\DEF_LC 2015-02-19 15-29-29\MML_BTX.M (Sequence Method)Last changed : 2/19/2015 3:29:29 PM by SYSTEMAdditional Info : Peak(s) manually integrated

min2 4 6 8 10 12 14

mAU

0

20

40

60

80

100

120

DAD1 G, Sig=260,8 Ref=off (DEF_LC 2015-02-19 15-29-29\092-0301.D)

1.1

61

1.7

85

Area

: 739

.773

7.5

93

===================================================================== Area Percent Report ===================================================================== Sorted By : SignalMultiplier : 1.0000Dilution : 1.0000Use Multiplier & Dilution Factor with ISTDs Signal 1: DAD1 G, Sig=260,8 Ref=off Peak RetTime Type Width Area Height Area # [min] [min] [mAU*s] [mAU] %----|-------|----|-------|----------|----------|--------| 1 1.161 BB 0.0592 124.82352 32.18995 12.5350 2 1.785 VB 0.0601 131.20634 33.17742 13.1759 3 7.593 MM 0.1208 739.77277 102.07124 74.2891 Totals : 995.80263 167.43860 ===================================================================== *** End of Report ***

Data File C:\CHEM32\1\DATA\DEF_LC 2015-02-19 15-29-29\092-0301.DSample Name: Natural_BTX

HPLC 1 2/19/2015 9:39:16 PM SYSTEM Page 1 of 1

S70

Co-injection (~1.5 : 1 Synthetic BTX/Natural BTX)

=====================================================================Acq. Operator : SYST

supplementary materials for...osit bume 2 meo me o h bu3sn oh oh sime3 meo me o h ohco oh bu3sn meo...

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