Asymmetric hydrogenation of olefins, carbonyl cpds. or nitriles - using transition metal complex of asymmetric amino-phosphine

摘要

New asymmetric aminophosphines are of formula (I) P(R1)x(NR2R3)3-x (I) (where R1 is alkyl, aryl, alkylaryl, cycloalkyl, alkoxy, aryloxy, alkylthio, arylthio, alkylphosphino, arylphosphino, or aminophosphino; x = 0-2; R2 and R3 are alkyl, aryl, alklaryl, aralkyl or cycloalkyl, at least one of which contains one or more asymmetric centres). In an examples R(-)-N-acetyl-phenylalamine is prepd. by hydrogenating alpha-acetamido-cinnamic acid in the presence of a catalyst prepd. from u-dichloro-tetrakis (ethylene)-dirhodium and N,N'-bis S(-)-d-methylbenzyl -N,N'-(diphenylphosphine)-ethylenediamine. The process is esp. useful for preparing optically active amino acids from the corresp. olefinically unsatd. amino acids. Prodts. of high optical purity (e.g. 73-84%) can be obtd. in certain cases.