Nickel Nanoparticle Catalyzed Mono‐ and Di‐Reductions of gem‐Dibromocyclopropanes Under Mild, Aqueous Micellar Conditions

Abstract

AbstractMild mono‐ and di‐hydrodehalogenative reductions of gem‐dibromocyclopropanes are described, providing an easy and green approach towards the synthesis of cyclopropanes. The methodology utilizes 0.5–5 mol % TMPhen‐nickel as the catalyst, which, when activated with a hydride source such as sodium borohydride, cleanly and selectively dehalogenates dibromocyclopropanes. Double reduction proceeds in a single operation at temperatures between 20–45 °C and at atmospheric pressure in an aqueous designer surfactant medium. At lower loading and either in the absence of ligand or in the presence of 2,2′‐bipyridine, this new technology can also be used to gain access to not only monobrominated cyclopropanes, interesting building blocks for further use in synthesis, but also mono‐ or di‐deuterated analogues. Taken together, this base‐metal‐catalyzed process provides access to cyclopropyl‐containing products and is achieved under environmentally responsible conditions.