Asymmetric Hydrogenation of Unsaturated Peptides

Abstract

Eleven unsaturated peptides, containing one or two dehydro-phenylalanyl (dehydro-Phe) residues and a C-terminal L-amino acid have been hydrogenated in the presence of palladium-on-charcoal. Hydrolysis o f the saturated peptides thus obtained gave optically active phenylalanine showing the occurrence of asymmetric induction during the hydrogenation. Both monoansaturated dipeptides and doubly unsaturated tripeptides with L-Glu, L-Leu and L-Val as chiral end-group afforded L-Phe in 40-50% optical yield. In the case of the trip ep t ide N-a ce ty I-(de hy dro -Ph e) -(dehy dro -Ty r) -L -Glu