Chapter 4, Problem 101P

Interpretation Introduction

Interpretation:

The assigning of configuration of each asymmetric center as R if –OH group is on the right and the configuration is S if the –OH is group in on left side for D-glucose has to be checked.

Concept introduction:

• Asymmetric center is a stereocenter which arises to a compound if any atom is bonded to four different groups.
• The stereo-descriptor for other carbohydrates of having more than one chiral center will be evaluated by the location of –OH group (right or left) of farthest chiral carbon from the carbonyl group. Such as,

If the –OH group is located in right side then, the carbohydrate is a D-sugar.

If the –OH group is located in left side then, the carbohydrate is a L-sugar.

• Configuration of a molecule:  The configurations of a molecule arise due to the spatial arrangement of atoms.  The configuration can be assigned by following CIP rules as follows.
• Assign numbering to the groups which are bonded to the chiral carbon based on the molecular weight and electronegativity.
• If the sequence of the numbering follows clockwise direction the chiral atom is assigned as R configuration.
• If the sequence of the numbering follows anticlockwise direction the chiral atom is assigned as S configuration.
• If the least priority group is on horizontal line in the fisher projection, then configuration is inverted to the obtained configuration from the above CIP rule which means R configuration becomes S and vice versa.