Stereodivergent organocatalytic intramolecular Michael addition/lactonization for the asymmetric synthesis of substituted dihydrobenzofurans and tetrahydrofurans

Chemistry. 2014 Jul 28;20(31):9762-9. doi: 10.1002/chem.201402684. Epub 2014 Jul 2.

Abstract

A stereodivergent asymmetric Lewis base catalyzed Michael addition/lactonization of enone acids into substituted dihydrobenzofuran and tetrahydrofuran derivatives is reported. Commercially available (S)-(-)-tetramisole hydrochloride gives products with high syn diastereoselectivity in excellent enantioselectivity (up to 99:1 d.r.syn/anti , 99 % eesyn ), whereas using a cinchona alkaloid derived catalyst gives the corresponding anti-diastereoisomers as the major product (up to 10:90 d.r.syn/anti , 99 % eeanti ).

Keywords: Michael addition; asymmetric catalysis; cinchona alkaloid; isothiourea; organocatalysis; oxygen heterocycles; stereodivergent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzofurans / chemical synthesis*
  • Benzofurans / chemistry
  • Catalysis
  • Furans / chemical synthesis*
  • Furans / chemistry
  • Stereoisomerism

Substances

  • Benzofurans
  • Furans