Chapter 17.2, Problem 2P

Interpretation Introduction

Interpretation:

The amino acids that have more than one asymmetric center have to be identified.

Concept Introduction:

Asymmetric center: Asymmetric or chiral center tetrahedral atom bonded to four different groups, it is indicated as *.

Example:

  

Configuration of Amino Acids:

In a Fischer projection, with the carbonyl group at the top and the R group at the bottom of the vertical axis and the amino group is on the right side is a D-amino acid; with the carbonyl group at the top and the R group at the bottom of the vertical axis and the amino group is on the left side is L-amino acid.

Rules for assigning $\left(R,S\right)$- configuration:

1. 1. Prioritize the four groups around the chiral center according to atomic number.
2. 2. Orient the chiral center such that the least priority substituent is pointing away from the viewer.
3. 3. Trace the path of priorities; is the path traced is clockwise, the chiral center is assigned as R. If the path is traced in anti-clockwise, the chiral center is assigned as S.