Chapter 23, Problem 93CP

(a)

Interpretation Introduction

Interpretation: The structures of 3 and 4 with diastereomeric centers have to be drawn

Concept Introduction:

Sodium cyanoborohydride is a strong reducing agent than sodium borohydride.  It reduces the carbonyl group into amine group in a rapid way.  So, it is called as reductive amination reactions.  Aldehyde or ketone group is reacted with primary amine in the presence of sodium cyanoborohydride as a reducing agent and a proton source in the reaction medium to produce secondary amines.

If a carbon is attached with four different groups without any elements of symmetry, then that center has a chirality center.  Diastereomers (sometimes called diastereoisomers) are a type of a stereoisomer.  Diastereomerism occurs when two or more stereoisomers of a compound have different configurations at one or more stereocenters and are not mirror images of each other.  When two diastereoisomers differ from each other at only one stereocenter, they are epimers.  Each stereocenter gives rise to two different configurations and thus increases the number of stereoisomers by a factor of two.

To find: Draw the structure of 3 and the reason for its production as a diastereomeric mixture

Do reductive amination in compound 2

(b)

Interpretation Introduction

Interpretation: The structures of 3 and 4 with diastereomeric centers have to be drawn

Concept Introduction:

An amide group is formed from an amine compound and the ester group.

If a carbon is attached with four different groups without any elements of symmetry, then that center has a chirality center.  Diastereomers (sometimes called diastereoisomers) are a type of a stereoisomer.  Diastereomerism occurs when two or more stereoisomers of a compound have different configurations at one or more stereocenters and are not mirror images of each other.  When two diastereoisomers differ from each other at only one stereocenter, they are epimers.  Each stereocenter gives rise to two different configurations and thus increases the number of stereoisomers by a factor of two.

To find: Draw the structure of 4 and determine the possibility of its production as a diastereomeric mixture

Decide the nature of the functional groups in compound 3