Asymmetric synthesis and catalytic activity of 3-methyl-β-proline in enantioselective anti-Mannich-type reactions

J Org Chem. 2013 Jul 19;78(14):7131-6. doi: 10.1021/jo4010316. Epub 2013 Jul 10.

Abstract

Enantiomerically pure 3-methyl-β-proline was synthesized using an asymmetric phase-transfer-catalyzed alkylation of a cyanopropanoate to establish the all-carbon stereogenic center. The catalytic activity of 3-methyl-β-proline in the Mannich-type reaction between a glyoxylate imine and ketones/aldehydes was subsequently investigated. The catalyst was designed and found to be more soluble in nonpolar organic solvents relative to the unsubstituted β-proline catalyst, and as a result allowed for added flexibility during optimization efforts. This work culminated in the development of a highly anti-diastereo- and enantioselective process employing low catalyst loading.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkylation
  • Catalysis
  • Molecular Structure
  • Proline / analogs & derivatives*
  • Proline / chemical synthesis
  • Proline / chemistry
  • Propane / analogs & derivatives
  • Propane / chemistry*

Substances

  • Proline
  • Propane