Y5

Question 1

RNH2 protecting groups

Answer 1

Cbz
Boc

Question 2

ROH protecting groups

Answer 2

acetyl
THP
TBS
benzyl

Question 3

RCOOH protecting groups

Answer 3

methyl ester
benzyl ester

Question 4

ketone/aldehyde protecting groups

Answer 4

acetals

Question 5

acetal
- addition
- removal

Answer 5

cat.H+

cat. H+, H2O

Question 6

acetyl
- addition
- removal

Answer 6

AcCl

cat. NaOMe, MeOH

Question 7

THP
- addition
- removal

Answer 7

cat. H+

H2O, cat. H+

Question 8

TBS
- addition
- removal

Answer 8

TBS-Cl, NaH or Et3N

CF3COOH (TFA) or TBAF

Question 9

Benzyl
- addition
- removal

Answer 9

Br-benzyl NaH

H2, Pd/C

Question 10

Cbz
- addition
- removal

Answer 10

Cbz, Na2CO3, H2O

H2, Pd/C, MeOH (decomp)

Question 11

Boc
- addition
- removal

Answer 11

Boc, NaOH, H2O

CF3COOH (decomp)

Question 12

methyl ester (MeOR)

Answer 12

MeOH, cat. H+ or SOCl2, MeOH

1. NaOH, H2O 2. H+

Question 13

benzyl ester (BnOR)

Answer 13

BnOH, cat. H+ or SOCl2, BnOH

1. NaOH, H2O 2. H2O or H2, Pd/C

Question 14

coupling reagent for amino acid formation of peptide bonds

Answer 14

DCC

Question 15

PCC
- reaction type
- results

Answer 15

oxidation

1 alcohol - aldehyde

Question 16

CrO3, H+
- reaction type
- results

Answer 16

jones oxidation

1 alcohol - carboxylic acid
(does not stop oxidation at aldehyde phase - use PCC)

2 alcohol - ketone

aldehyde - carboxylic acid

Question 17

1. NaBH4, EtOH
2. H2O
   - reaction type
   - results

Answer 17

reduction (chemoselective)
- will react with ketones and not esters (using 1 equiv.)

aldehyde - 1 alcohol

ketone - 2 alcohol

Question 18

1. LiAlH4, EtO2 (violent reaction in protonated environment)
2. H2O
   - reaction type
   - results

Answer 18

reduction (non-chemoselective)
- will react with ketones/aldehydes and esters

ester - aldehyde - 1 alcohol

anhydride - aldehyde - 1 alcohol

acid chloride - aldehyde - 1 alcohol
(will not stop reduction at aldehyde)

ketone - 2 alcohol

Question 19

ester formation from carboxylic acid

Answer 19

MeOH, cat. H+

Question 20

formation of alkene grignards

Answer 20

R-Br + Mg - (EtO2 (dry) ) - R-MgBr

• requires protic quench after reaction

Question 21

formation of alkyne grignards

Answer 21

R—H + R-MgBr - (EtO2 (dry)) - R—MgBr

• requires protic quench after reaction

Question 22

organo-lithiums

Answer 22

stronger nucleophile than organomagnesiums
- can react well with carboxylic acids to form ketones

Question 23

regioselectivity

Answer 23

the preferential direction for bond formation/breaking
- e.g. EDG, EWG

Question 24

stereoselectivity

Answer 24

the preferential formation of one stereoisomer over another
- e.g. conjugated addition

Question 25

stereospecificity

Answer 25

referring to reactions where starting material differ only by configuration and each form opposite stereoisomers

Question 26

chemoselectivity

Answer 26

the preferential reaction of reagents with specific functional groups - e.g. use NaBH4 to reduce only ketones in the presence of esters