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Part 2:

1. (14 pt) Draw the organic product expected from each of the following reactions.  Be sure to
indicate stereochemistry where appropriate and to include stereoisomers if any.  In case two or more
stereoisomers are formed, label their relationship as diastereomers, enantiomers, structural isomers,
or conformers.

2. (10 pt)  (A) Draw Fisher projections for (2R, 3S)-2-bromo-3-chlorobutane and (2S, 3R)-2-bromo-
3-chlorobutane, with the carbon chain on the vertical line.  Label each structure as (2R, 3S) or (2S,
3R).

(B) Assume that you have a mixture of equal amount of each of the above compounds. Can they be
separated into two containers based on physical properties such as b.p., m.p., etc.? If yes, which
technique would you use?  If no, briefly explain why not.

The two compounds as drawn are enantiomers which have identical b.p. and other physical properties
(different only towards plane polarized light).  Therefore they can't be separated based on physical
properties alone.

I

+ NaO C

O

CH

3

S

N

2

(A)

CH

3

O

C

O

C

Cl

H

CH

3

D

+      NaOCH

3

S

N

2

(B)

C

CH

3

O

H

CH

3

D

C

I

CH

3

CH

2

CH

3

CH

3

CH

2

CH

2

H

2

O     +

S

N

1

(C)

C

OH

CH

3

CH

2

CH

3

CH

3

CH

2

CH

2

C

HO

CH

3

CH

2

CH

3

CH

3

CH

2

CH

2

+

about 50% of each

CH

3

H

Br

Cl

H

CH

3

2S, 3R

CH

3

H

Br
Cl

H

CH

3

2R, 3S

Comments:

Organic chemistry (questions with answers)

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