Highly Enantioselective Synthesis of Chiral Cyclic Amino Alcohols and Conhydrine by Ruthenium-Catalyzed Asymmetric Hydrogenation

A highly efficient enantio- and diastereoselective synthesis of chiral cis-beta-N-alkyl/arylamino cyclic alcohols has been realized by asymmetric hydrogenation of racemic alpha-amino cyclic ketones via DKR catalyzed by [RuCl(2)((S)-Xyl-SDP)((R,R)-DPEN)]. The enantioselectivities of the reaction were up to 99.9% ee with 99:1 cis-selectivities. A practical catalytic asymmetric synthesis of all four isomers of conhydrine was also developed.