Mechanisms

Question 1

alkene → alkane

Answer 1

CH2 = CH2 + H2/Pd (catalyst) → CH3CH3

Question 2

alcohol oxidation

Answer 2

1° alcohol → aldehyde → carboxylic acid
2° alcohol → ketone
3° alcohol → cannot be oxidized further

oxidizing agents: O3, Cr2O7, CrO4, KMnO4, Jones, Collins, PCC, PDC

Question 3

alcohol reduction

Answer 3

NaBH4 → can only reduce aldehydes and ketones

LiAlH4 and H2/pressure → can reduce aldehydes, ketones, carboxylic acids, esters

Question 4

alcohol protection

Answer 4

TMS or MOM

*** acidification will remove both protecting groups

Question 5

OH with SOCl2/PBr3

Answer 5

ROH + SOCl2 → RCl

ROH + PBr3 → RBr

Question 6

formation of tosylates/mesylates

Answer 6

Tosyl-Cl + ROH → Tosyl-OR + HCl

***SN2

Question 7

alcohol → alkene

Answer 7

CH3CH2OH + H2O ⟷ CH3CH2OH2+ ⟷ CH2=CH2

alkene → favored by hot, concentrated acid

alcohol → favored by cold, dilute acid

Question 8

Grignard synthesis

Answer 8

carbonyl → alcohol + extension of carbon chain

CH3COCH3 + CH3MgBr → CH3COH(CH3)2

Question 9

substitution of epoxide

Answer 9

Question 10

alcohol → alkyl halide

Answer 10

SN1: R3COH + HCl → R3COH2+ + Cl- → R3C+ + H2O → R3CCl

SN2: CH3OH + HCl → CH3OH2+ + Cl- → CH3Cl + H2O

Question 11

pinacol rearrangement

Answer 11

vic-diol + hot acid → ketone or aldehyde

trisubstituted → aldehyde
tetrasubstituted → ketone