Enantioselektive Katalyse VII. Komplexe von (P(R,S),3R,4R,P′(R,S))-3,4-Bis(phenylphosphino)pyrrolidinen. Die Darstellung optisch reiner 1,2-Bisphosphanliganden mit vier Stereozentren, die zusätzliche funktionnelle Gruppen enthalten

Diastereomeric mixtures of the palladium, the platinum, and the rhodium complexes were prepared from P(R,S),3R,4R,P′(R,S)]-3,4-bis(phenylphosphino)pyrrolidine (1a). The phosphorus atoms in bis(P(R,S),3R,4R,P′(R,S))-1-(t-butoxycarbonyl)-3,4-bis(phenylphosphino)pyrrolidine-P,P′]dihalogenopalladium (2) can be alkylated stereoselectively with iodomethane. The P---H bonds in 2 open epoxides, and add to Michael systems, to give new ligands, which can be split off from the palladium with cyanide. The three isomerically pure (PR,3R,4R,P′R)(PS,3R,4R,P′S)(PR,3R,4R,P′S)]-1-(t-butoxycarbonyl)-3,4- bis(2-cyanoethyl)phenylphosphino]pyrrolidines were prepared via the neutral diiodopalladium complexes. (PS,3R,4R,P′S)1-(t-butoxycarbonyl)-3,4-bis(2-cyanoethyl)phenylphosphino]pyrrolidine-P,P′]diiodopalladium(II) (14-1) was characterised by X-ray crystallography.