L-Pipecolinic acid derived Lewis base organocatalyst for asymmetric reduction of N-aryl imines by trichlorosilane: effects of the side amide group on catalytic performances

Org Biomol Chem. 2013 Feb 7;11(5):787-97. doi: 10.1039/c2ob26772a. Epub 2012 Dec 7.

Abstract

A series of N-formamides derived from pipecolinic acid have been synthesized and tested as Lewis base catalysts for the enantioselective reduction of N-aryl imines by trichlorosilane. Through the investigation of the structure-efficacy relationship between the side amide group and catalytic performance, several highly effective catalysts were discovered. In particular, arylamido-type catalyst 5i and non-arylamido-type catalyst 6c exhibited high reactivity and enantioselectivity, furnishing the reduction of a wide variety of N-aryl imines with high isolated yields (up to 98%) and ee values (up to 96%) under mild conditions. Moreover, these two catalysts complement each other in terms of their tolerances to nonaromatic ketimines and non-methyl ketimines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Formamides / chemistry*
  • Imines / chemistry*
  • Lewis Bases / chemistry*
  • Pipecolic Acids / chemistry*
  • Silanes / chemistry*

Substances

  • Formamides
  • Imines
  • Lewis Bases
  • Pipecolic Acids
  • Silanes
  • trichlorosilane