summary organic reactions

7/30/2019 Summary Organic Reactions

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SUMMARY OF ORGANIC REACTIONSKarl Separa Imed 2018

Remember: When Carbocation in present in the intermediate, perform Hydride Shift or Methyl Shift with the Halogen ion to achieve higher stability. Also take into account steric effects when choosingattachment site.

RXN Reactant Catalyst, Solvent, Redox Agent Products NotesFREE RADICAL SUBSTITUTION Alkane (R) + X2

Benzyl or Allyl + X 2

Allyl + NBS (N-bromosuccinimide)

UV light, High Temperature

High temperature

UV or High Temp in peroxide

R-X, H-X

R-X, H-X

R-X, succinimide

Use relative stabilities of radicals (3 > 2> 1)For Cl: use statistics (3 5.0, 2 3.8, 1 1.0)

For Br: use stability of radicals

Stability of radicals: benzyl, allyl, 3, 2, 1, vinyl, methyl

Remember that internal alkenes are more stable than terminalalkenes

ELECTROPHILIC ADDITION

Halogenation with Alkene

Hydrohalogenation

Special ReactionsOxymercuration - Reduction

Hydroboration Oxidation

Addition of PeroxideHydrogenation

Alkene (R) + H -X

R + H2OR + Alcohol

R + X2

R + X2

Alkyne (R) + H -XR + H2OR + X2

R + H2O

R + H2O

R

R

R + H-XR + H2

None

Acid (H+) at 140 CAcid (H+)

Inert solvent (ex. CH 2Cl2)

In H2O

NoneDiprotic acid (ex. H 2SO4)Inert solvent (ex. CH 2Cl2)

Hg(OAC)2 and reduced by Sodiumborohydride NaBH 4

Diprotic acid (ex. H 2SO4) in HgSO 4

Borane BH 3 accepts e- pair, addingNaOH, Hydrogen Peroxide H 2O2 and

H2O

Disiamylborane accepts e- pair,adding adding NaOH, Hydrogen

Peroxide H 2O2 and H 2O

PeroxideMetal Catalyst (Pt, Pd, Ni)

R-X

Alcohol, H 3O+

EtherAlways Vicinal-Anti dihalide

Halohydrin, H-X

Geminal dihalideKetone-enol tautomerism

Tetra-Haloalkane

Alcohol, Hg, AcO -, AcOH

Ketone-enol, H 2O, Hg2+

Alcohol

Aldehyde (if terminal alkene isused)

R-XR

Use carbocation/radical stabilityUse Markovnikov: Hydrogen bonds to Carbon with more H, Halogen

bonds to Carbon with less H

Hydration: Obey MarkovnikovObey Markovnikov

Vicinal: Halogens are located in adjacent Carbons; Anti: Halogens attrans config; no carbocations formed hence no rearrangementsHalohydrin (instead of 2 Halogens attached, 1 Halogen is replaced

with OH-group which was taken from the water solvent)

Reduction: increase in C-H bonds, decrease in C-O, C -N, C-X bonds;No carbocations formed hence no rearrangements

Anti-Markovnikov: in BH 3, one Hydrogen attaches to C of alkene withless number of Hydrogen atoms and remaining BH 2 attaches to the

other Carbon; BH 2 is then replaced by OH group; No rearrangementsdue to carbocation

Anti-Markovnikov

Anti-Markovnikov, No rearrangementsMetal catalysts are insoluble in the mixture; When hydrogenated,alkene releases heat (heat of hydrogenation); The two Hydrogen

attach themselves to the 2 Carbons involved in the double bond;Smaller heats=more stable; alkyl substituents bonded to C-atoms of alkene has stabilizing effect = More alkyl subsitutents, greater

stability or fewer Hydrogens, greater stability.


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Oxidation

Ozonolysis

R + H2

R

R

Metal Catalyst

MnO 4- in H2O

O3 in Zn and H 2O/Acetic acid

R R

Carboxylic Acid RCOOH, CO 2,H2O

Varies depending on Substratefunctional group

Reaction can be stopped at Alkene stage using Lindlar Catalyst(precipitating Pd on CaCO 3 and treating it with Pb (II) acetate and

quinoline); results in a cis alkene

Could also favor trans alkene if one uses Na or Li in NH 3 (liquid) at -78 C

Oxidize an alkyne RCOOH, Oxidize an alkene ROHRCOOH Aldehye ROH

Double bond breaks and an Oxygen attaches to each Carbon atomthat was previously involved in the bond

ELECTROPHILIC AROMATICSUBSTITUTION

Halogenation

NitrationSulfonation

Friedel-Crafts Acylation

Friedel-Crafts Alkylation

Clemmensen Reduction andWolff-Kishner reduction

Gatterman-Kock Formylation

Reducing a Nitro Group

Side Chain of SubstitutedBenzene:

a. Halogenation of Alkyl sidechain

b. Oxidation of Alkyl sidechain

Benzene + Br 2Benzene + Cl 2Benzene + I 2

Benzene + HNO 3Benzene + H 2SO4

Benzene + acyl halideBenzene + acid

anhydride

Benzene + R-X

Benzene w/ AcylBenzene w/ Acyl

Benzene + FormylChloride

Nitrobenzene

Alkyl Benzene + X 2

Alkyl Benzene

FeBr 2 catalyst (Lewis Acid)FeCl2 catalyst (Lewis Acid)

Oxidizing Agent to transform I 2 2I+

Sulfuric acid H 2SO4Fuming or concentrated sulfuric

acid

AlCl3 catalyst (Lewis Acid) in H 2OAlCl3 catalyst (Lewis Acid) in H 2O

AlCl3 catalyst (Lewis Acid)

Zn(Hg), HCl, heatH2NNH2, HO

-, heat

AlCl3/CuCl3

Sn, HCl (use metal and HCl)

UV, Heat

Hot KMnO 4

Bromobenzene, HBrChlorobenzene, HCl

Iodobenzene, I +

Nitrobenzene, H 2OBenzenesulfonic acid, H 2O

Benzene w/ R-C=O, H-XBenzene w/ R-C=O, RCOOH

Benzene-R, H-X

Benzene-RBenzene-R

Benzaldehyde (-COH)

Protonated Aniline (Anilinium)

Benzene-(Alkyl halide), H-X

Always benzoic acid

General Steps in S EAr: (1) benzene reacts with an electrophile forminga carbocation intermediate which is approximated by 3 resonance

structures, (2) a base in the reaction mixture pulls off a proton fromthe carbocation intermediate and the electrons that held the proton

move into the ring to establish aromaticity

Nitric acid HNO 3 receives H from H 2SO4, this forms H 2O and NO 2+

One H 2SO4 molecule donates one of its Hydrogen to another H 2SO4 which in turn produces H 2O. The second H 2SO4 which is now HSO 3

donates its sole H to H 2O producing H 3O+ and SO 3

Acyl: R-C=O; for FC reactions, benzene w/ amino groups dontundergo alkylation or acylation because amino group becomes a

powerful electron-withdrawing group by the lewis acid

Major disadvantage of FCA is that there are Carbocationrearrangements, to solve this, use acylation followed by reduction :

Benzene in acylation benzene w/ R-C=O; to remove O, do anotherrxn where you will add H 2 and use Pd as catalyst (Hydrogenation)

Used to reduce acyl carbon(to reduce means to replace C=O bond with 2 C-H bonds)

To form formyl chloride: CO + HCl (at high pressure) O=CH-Cl

Can still be continued by reacting Anilinium ion with OH - to produceaniline and H 2O

Alkyl portion: undergoes FR substitution characteristic of alkanesAromatic Ring: undergoes E + substitution characteristic of benzene

Convert all alkyl substituents, regardless of length, into COOH


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NUCLEOPHILIC AROMATICSUBSTITUTION

a. Addition Elimination Aryl halide Ar-X + OH -

Aryl Halide w/ 1EWG + OH -



350 C, high Pressure, H 2OAq. NaHCO3, 130

CAq. NaHCO3, 100

CAq. NaHCO3, 35

C

PhenolNitrophenol

DinitrophenolTrinitrophenol

summary organic reactions

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