Cobalt-Catalyzed Selective Unsymmetrical Dioxidation of gem-Difluoroalkenes

J Org Chem. 2020 Aug 21;85(16):10451-10465. doi: 10.1021/acs.joc.0c00415. Epub 2020 Aug 5.

Abstract

gem-Difluoroalkenes represent valuable synthetic handles for organofluorine chemistry; however, most reactions of this substructure proceed through reactive intermediates prone to eliminate a fluorine atom and generate monofluorinated products. Taking advantage of the distinct reactivity of gem-difluoroalkenes, we present a cobalt-catalyzed regioselective unsymmetrical dioxygenation of gem-difluoroalkenes using phenols and molecular oxygen, which retains both fluorine atoms and provides β-phenoxy-β,β-difluorobenzyl alcohols. Mechanistic studies suggest that the reaction operates through a radical chain process initiated by Co(II)/O2/phenol and quenched by the Co-based catalyst. This mechanism enables the retention of both fluorine atoms, which contrasts most transition-metal-catalyzed reactions of gem-difluoroalkenes that typically involve defluorination.

Publication types

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

MeSH terms

  • Catalysis
  • Cobalt*
  • Fluorides
  • Fluorine*

Substances

  • Fluorine
  • Cobalt
  • Fluorides