Reduction of gem-Dibromocyclopropanes with Dialkyl Phosphonate and Amine

Abstract

Reduction of 7, 7-dibromobicyclo[4.1.0]heptane was examined in the presence of amine (triethylamine, tributylamine, N, N-diethylaniline etc. ) to evaluate dialkyl phosphonate (R=Me, Et, or i-Pr) as a reducing reagent. A combination of diethyl phosphonate and triethylamine was found to work efficiently for the selective reduction to 7-bromobicyclo[4.1.0]heptane as compared with other known debromination agents. Similarly gem-dibromocyclopropanes bearing the trimethylsilyl group were reduced to the corresponding monobromocyclopropanes under the present conditions.