4-Dimethylamino pyridine-promoted one-pot three-component regioselective synthesis of highly functionalized 4H-thiopyrans via heteroannulation of β-oxodithioesters

ACS Comb Sci. 2012 Mar 12;14(3):224-30. doi: 10.1021/co200203e. Epub 2012 Feb 7.

Abstract

A highly convergent and regioselective heteroannulation protocol for the synthesis of hitherto unreported highly substituted 2-amino-4-(aryl/alkyl)-5-(aroyl/heteroaroyl)-3-(cyano/carboalkoxy)-6-methylthio-4H-thiopyran derivatives has been developed. This one-pot three-component domino coupling of β-oxodithioesters, aldehydes, and malononitrile/ethyl or methyl cyanoacetate is promoted by 4-dimethylamino pyridine (DMAP) in solvent (dichloromethane (DCM)) as well as under solvent-free conditions. Systematic optimization of reaction parameters identified that the three-component coupling (3CC) protocol is tolerant to a wide array of functionality providing densely functionalized 4H-thiopyrans in excellent yields. The merit of this cascade Knoevenagel condensation/Michael addition/cyclization sequence is highlighted by its high atom-economy, excellent yields, and efficiency of producing three new bonds (two C-C and one C-S) and one stereocenter in a single operation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amines / chemistry*
  • Esters / chemistry*
  • Models, Molecular
  • Molecular Structure
  • Pyrans / chemical synthesis*
  • Pyrans / chemistry
  • Pyridines / chemistry*
  • Stereoisomerism
  • Sulfhydryl Compounds / chemical synthesis*
  • Sulfhydryl Compounds / chemistry
  • X-Ray Diffraction

Substances

  • Amines
  • Esters
  • Pyrans
  • Pyridines
  • Sulfhydryl Compounds
  • thiopyran