Synth fest

Question 1

How to oxidise alcohols to ketones/COOH

Answer 1

CrO3, H2SO4, H2O

Question 2

How to oxidise primary alcohols to aldehydes?

Answer 2

PDC (avoid water)

Question 3

Strong reducing agent that reduces everything?

Answer 3

LiAlH4
(includes nitriles+amides to amines, alkyl halides to alkanes, esters+acyl cls to primary alcohols)

Question 4

What reduces ketones and aldehydes only?
1,4/1,2

Answer 4

Mild reducing agent
NaBH4
(doesn’t reduce amides, esters, acyl cls)
Presence of CuI- 1,4 red
Presence CeCl3- 1,2 red

Question 5

What does DIBALH do?

Answer 5

Selective reduction of esters and nitriles to aldehydes

Question 6

Alcohol to ether?

Answer 6

NaH, RI

Question 7

Alcohol to tosylate?

Answer 7

TsCl, py

Question 8

Alcohol to halo alkane?

Answer 8

PX3

Question 9

Halo alkane to Grignard reagent?

Answer 9

Mg, (diethyl) ether

Question 10

COOH to acyl cl

Answer 10

SOCl2

Question 11

Nitrile to amide?

Answer 11

NaOH

Question 12

Tosyl to amine?

Answer 12

i) NaN3 (makes azide)
ii) reduce w/ H2, Pd (or LiAlH4)

Question 13

How to protect/deprotect with silyl ethers?
Why?

Answer 13

Alcohols protected
TBDMSCl + imidazole - OH to OTBDMS
Deprotect with TBAF i.e Bu4NF
Bulky, steric effects

Question 14

How to protect ketones

Answer 14

Acetals

Question 15

Wittig reaction (making alkenes)

Answer 15

Ylides, Ph3P=R (from phosphonium salt and base) and carbonyls
R swaps with O of C=O
Reactive ylides- R=alkyl
Moderate ylides- R=Ph
Stabilised ylides- R=EWG

Question 16

How to make alkynes

Answer 16

Alkyne + base (e.g BuLi) then electrophile
E+ replaces H of alkyne

Question 17

Secondary alcohols from aldehydes?

Answer 17

Grignard

Question 18

Tertiary alcohols from esters?

Answer 18

Grignard

Question 19

How are dithianes used?

Answer 19

React aldehydes to ketones
BuLi, makes them into good Nu- to E+
Hg2+, H2O to hydrolyse
Can be used for 1,2 relationship

Question 20

Nitrile to amine?

Answer 20

Reduction, H2, PtO2