Synthesis of gem-Diborylcyclopropyl Ketones via Conjugate Addition of Chlorodiborylmethane to α,β-Unsaturated Ketones

The carbanion derived from chlorodiborylmethane can act as a soft nucleophile, while the halogen substituent can subsequently function as a leaving group. Taking advantage of this feature, we herein have developed an efficient synthesis of gem-diborylcyclopropyl ketones from a diverse range of enone substrates. We also demonstrated the synthetic utility of this protocol by leveraging the highly transformable nature of the cyclopropyl moiety and the C-B bonds.