Synthesis and Molecular Structure of Stable Derivatives of (E)- and (Z)-Dehydrophenylalanine

Abstract

Bromination of the phenylalanine derivative (1) affords the bromides (2) and (3), which react by stereospecific anti-elimination to give the isomeric pair of stable dehydrophenylalanine derivatives (4) and (5). The molecular structures of (4)and (5), which have been determined by X-ray crystallographic analysis, correlate with their lack of interconversion and the unusual stability of (5).