Chapter 25, Problem 62PP

Interpretation Introduction

Interpretation:

The alkene required for the synthesis of L-histidine by asymmetric catalytic hydrogenation need to be identified.

Concept introduction:

Asymmetric catalytic hydrogenation is a reaction in which the alkene substrate is reduced to a saturated compound by addition of two atoms of hydrogen.  When chiral catalyst is used a enantioselective product is obtained.  This technique uses a chiral catalyst so that the amino acids can be prepared with high enantiomeric excess.

The final step after hydrogenation is the hydrolysis of the protected group of amine.  The general scheme can be shown as,