Efficient preparation of an N-aryl β-amino acid via asymmetric hydrogenation and direct asymmetric reductive amination en route to Ezetimibe
摘要:
Two routes for the preparation of an N-aryl beta-amino acid, an important precursor for the cholesterol-lowering drug Ezetimibe, were investigated. The first pathway proceeds via an Rh- or Ir-catalyzed asymmetric hydrogenation of N-aryl enamine giving the desired product with up to 82% ee. The other pathway involves a direct asymmetric reductive amination (DARA) of the beta-keto ester which yielded the beta-amino ester in high yield and 97% ee. Subsequent copper-catalyzed N-arylation gave the target compound. (C) 2010 Elsevier Ltd. All rights reserved.