Silicon-based Lewis acid assisted cinchona alkaloid catalysis: highly enantioselective aza-Michael reaction under solvent-free conditions

Org Lett. 2011 Dec 16;13(24):6508-11. doi: 10.1021/ol202803b. Epub 2011 Nov 16.

Abstract

The study showed that a combination of an achiral silicon-based Lewis acid and chiral Lewis base, such as iodotrimethylsilane (TMSI) and cinchonine, generated a highly enantioselective catalyst system under solvent-free conditions which gave aromatic β-amino ketones with up to >99% ee. Mechanistic studies demonstrate the enhanced asymmetric induction may be due to the combined and competitive activation of a carbonyl moiety of chalcone with cinchonine and the silicon-based Lewis acid in the aza-Michael reaction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Chalcones / chemistry*
  • Cinchona Alkaloids / chemical synthesis*
  • Cinchona Alkaloids / chemistry
  • Ketones / chemical synthesis
  • Ketones / chemistry
  • Lewis Acids / chemistry
  • Molecular Structure
  • Silanes / chemical synthesis*
  • Silanes / chemistry*
  • Stereoisomerism

Substances

  • Chalcones
  • Cinchona Alkaloids
  • Ketones
  • Lewis Acids
  • Silanes