Two-Phase Dibromocyclopropanation of Unsaturated Alcohols Using Flow Chemistry

Molecules. 2020 May 19;25(10):2364. doi: 10.3390/molecules25102364.

Abstract

Dibromocyclopropanations are conventionally done by addition of dibromocarbene to alkenes under phase-transfer conditions in batch reactions using a strong base (50% NaOH (aq)), vigorous stirring and long reaction times. We have shown that cyclopropanation of unsaturated alcohols can be done under ambient conditions using continuous flow chemistry with 40% (w/w) NaOH (aq) as the base. The reactions were generally rapid; the yields were comparable to yields reported in the literature for the conventional batch reaction.

Keywords: CHBr3; Makosza reaction; dibromocyclopropanation; flow chemistry; phase-transfer catalysis; unsaturated alcohols.

MeSH terms

  • Alcohols / chemistry*
  • Alcohols / metabolism
  • Alkenes / chemistry*
  • Catalysis
  • Cyclopropanes / chemistry*
  • Cyclopropanes / pharmacology

Substances

  • Alcohols
  • Alkenes
  • Cyclopropanes
  • cyclopropane