Enantioselective polyene cyclization via organo-SOMO catalysis

J Am Chem Soc. 2010 Apr 14;132(14):5027-9. doi: 10.1021/ja100185p.

Abstract

The first organocatalytic enantioselective radical polycyclization has been accomplished using singly occupied molecular orbital (SOMO) catalysis. The presented strategy relies on a selective single-electron oxidation of chiral enamines formed by condensation of polyenals with an imidazolidinone catalyst employing a suitable copper(II) oxidant. The reaction proceeds under mildly acidic conditions at room temperature and shows compatibility with an array of electron-poor as well as electron-rich functional groups. Upon termination by radical arylation followed by subsequent oxidation and rearomatization, a range of polycyclic aldehydes were accessed (12 examples, 54-77% yield, 85-93% ee). The enantioselective formation of up to six new carbocycles in a single catalyst-controlled cascade is described. Evidence for a radical-based cascade mechanism is indicated by a series of experimental results.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehydes / chemistry
  • Catalysis
  • Cyclization
  • Imidazolidines / chemistry*
  • Molecular Structure
  • Polyenes / chemical synthesis*
  • Polyenes / chemistry
  • Stereoisomerism

Substances

  • Aldehydes
  • Imidazolidines
  • Polyenes