Stereochemical studies. LX. Neighboring phenyl group participation. I. Stereospecific transformation of L-phenylalanine to optically active tropic acid.

Abstract

Trifluoroacetolysis of (S)-3-phenyllactic acid ester sulfonate ((S)-7), obtained from L-phenylalanine via nitrous acid deamination followed by ethanolysis, afforded (R)-tropic acid ester ((R)-8) in good yield by phenyl migration with inversion, while acetolysis followed by ethanolysis afforded (R)-phenyllactic acid ester ((R)-6b) in good yield by substitution with inversion. Mechanistic aspects of these reactions are discussed.