Enantioselective one-pot conjugate addition of grignard reagents to cyclic enones followed by amidomethylation

J Org Chem. 2012 Jan 6;77(1):760-5. doi: 10.1021/jo202146f. Epub 2011 Dec 8.

Abstract

Enantioselective conjugate addition of Grignard reagents to enones, catalyzed by Cu-Taniaphos or Josiphos complex, affords chiral enolates. Ensuing one-pot Mannich reaction with TiCl(4)-generated imine leads to aminocarbonyl compounds with benzyloxycarbonyl-protected nitrogen. Both diastereomers of these compounds are isolated in moderate yields but high enantiomeric purities (up to er 97.5:2.5).