Asymmetric hydrogenation of dehydrodipeptide esters bearing different protective groups.
N-[(Z)-N-Benzoyl- or N-Boc-(2-fluorophenyl)dehydroalanyl]-(R)- or (S)-phenylalanine esters were synthesized and hydrogenated to give the corresponding dipeptide derivatives with optical yields in the range of 53-87% de using the cationic rhodium complexes of PROPRAPHOS and BPPM. The efficiency of chiral diphosphine ligands as well the effect of the chiral center in the substrate on the catalytic asymmetric induction was studied.
Institut für Organische Katalyseforschung, Universität Rostock e.V., Federal Republic of Germany. cdoebl@chemie1.uni-rostock.de
C
C
Döbler
H J
HJ
Kreuzfeld
C
C
Fischer
M
M
Michalik
D000596:Amino Acids / Q000737:chemistry; D004151:Dipeptides / Q000138:chemical synthesis* / Q000737:chemistry; D004952:Esters / Q000138:chemical synthesis / Q000737:chemistry; D006865:Hydrogenation
D000596:Amino Acids; D004151:Dipeptides; D004952:Esters