Catalytic [5 + 1]-Cycloadditions of Vinylcyclopropanes and Vinylidenes

J Am Chem Soc. 2020 Mar 11;142(10):4598-4603. doi: 10.1021/jacs.0c00356. Epub 2020 Feb 27.

Abstract

Polysubstituted cyclohexenes bearing 1,3 (meta) substitution patterns are challenging to access using the Diels-Alder reaction (the ortho-para rule). Here, we report a cobalt-catalyzed reductive [5 + 1]-cycloaddition between a vinylcyclopropane and a vinylidene to provide methylenecyclohexenes bearing all-meta relationships. Vinylidene equivalents are generated from 1,1-dichloroalkenes using Zn as a stoichiometric reductant. Experimental observations are consistent with a mechanism involving a cobaltacyclobutane formed from a [2 + 2]-cycloaddition between a cobalt vinylidene and a vinylcyclopropane.

Publication types

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

MeSH terms

  • Catalysis
  • Cobalt / chemistry
  • Coordination Complexes / chemistry
  • Cycloaddition Reaction
  • Cyclohexenes / chemical synthesis*
  • Cyclopropanes / chemistry*
  • Models, Chemical
  • Vinyl Compounds / chemistry*

Substances

  • Coordination Complexes
  • Cyclohexenes
  • Cyclopropanes
  • Vinyl Compounds
  • Cobalt