Catalysis of 3-pyrrolidinecarboxylic acid and related pyrrolidine derivatives in enantioselective anti-Mannich-type reactions: importance of the 3-acid group on pyrrolidine for stereocontrol

J Am Chem Soc. 2008 Jan 23;130(3):875-86. doi: 10.1021/ja074907+. Epub 2007 Dec 29.

Abstract

The development of enantioselective anti-selective Mannich-type reactions of aldehydes and ketones with imines catalyzed by 3-pyrrolidinecarboxylic acid and related pyrrolidine derivatives is reported in detail. Both (3R,5R)-5-methyl-3-pyrrolidinecarboxylic acid and (R)-3-pyrrolidinecarboxylic acid efficiently catalyzed the reactions of aldehydes with alpha-imino esters under mild conditions and afforded anti-Mannich products with high diastereo- and enantioselectivities (anti/syn up to 99:1, up to >99% ee). For the reactions of ketones with alpha-imino esters, (R)-3-pyrrolidinecarboxylic acid was an efficient catalyst (anti/syn up to >99:1, up to 99% ee). Evaluation of a series of pyrrolidine-based catalysts indicated that the acid group at the beta-position of the pyrrolidine ring of the catalyst played an important role in forwarding the carbon-carbon bond formation and in directing anti-selectivity and enantioselectivity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehydes / chemistry*
  • Catalysis
  • Imines / chemistry*
  • Ketones / chemistry*
  • Molecular Structure
  • Proline / analogs & derivatives*
  • Proline / chemistry
  • Pyrrolidines / chemistry*
  • Stereoisomerism

Substances

  • 5-methyl-3-pyrrolidinecarboxylic acid
  • Aldehydes
  • Imines
  • Ketones
  • Pyrrolidines
  • Proline
  • pyrrolidine
  • beta-proline