Patent ID: 7576118
Filing Date: 2009-08-18
Classification: C07B,C07D

Abstract:
1. An asymmetric hydrogenation process for the preparation of a compound of formula I or a salt thereof in at least 50% enantiomeric excess (ee) wherein n is 1 or 2, R 1 is Br or SO 2 CH 3 , and R 2 is H, benzyl, 4-nitrobenzyl, 4-aminobenzyl, 4-trifluoromethylbenzyl or 4-chlorobenzyl, which comprises: treating a compound of formula II or a salt thereof with a metal-chiral ligand and a hydrogen donor wherein when the hydrogen donor is H 2 , the process is carried out at a pressure of from about 0 to about 500 pounds per square inch gauge (psig), and wherein said metal-chiral ligand is (a) a ruthenium-axially chiral phosphine ligand complex, or (2) a rhodium chiral ferrocenyl phosphine ligand complex, or (3) a rhodium-TMBTP complex.