Stereocontrolled synthesis of deuterated phenylalanine derivatives through manipulation of an N-phthaloyl protecting group for the recall of stereochemistry. Application in the study of phenylalanine ammonia lyase

The enantiomers of [2-²(H₁]phenylalanine and all four stereoisomers of [2,3-²H₂]phenylalanine) have been prepared from (S)-phenylalanine through the introduction of a chiral centre onto an N-phthaloyl protecting group for the recall of stereochemistry. Studies of the interaction of these labelled phenylalanines with (S)-phenylalanine ammonia lyase show that both the C-2 and C-3 hydrogens of the product trans-cinnamate undergo exchange with solvent in the presence of the enzyme. The mechanistic implications of this observation are discussed.