PHOSPHINITES OF CARBOHYDRATES AS CHIRAL LIGANDS FOR ASYMMETRIC SYNTHESIS CATALYZED BY COMPLEXES .1. HYDROGENATION OF AMINO-ACID PRECURSORS BY RHODIUM(I) CHELATES OF METHYL 4,6-O-BENZYLIDENE-2,3-BIS-O-(DIPHENYLPHOSPHINO)-ALPHA-D-GLUCOPYRANOSIDES

A simple method for preparing carbohydrate-bis-phosphinites of methyl α-D-glucopyranosides of glucose and galactose protected by benzylidene groups in 4,6-position leads to chelating ligands which are useful in the asymmetric hydrogenation of prochiral aminoacid precursors catalyzed by rhodium(I), producing optical yields up to 75%. Cationic complexes are particularly active. © 1979 Akadémiai Kiadó.