Reductive Deoxygenation of Ketones with Silanes Catalyzed by Proton-Exchanged Montmorillonite to Olefin or Methylene Compounds

Abstract We have developed a novel process for the reductive deoxygenation of ketones using silanes, which affords either olefin or methylene products. The reaction is catalyzed by proton-exchanged montmorillonite, a solid acid catalyst. Notably, cyclic or linear aliphatic ketones with carbonyl groups flanked by two primary carbon atoms selectively yield olefins. 1,2-Dibromides can also be produced directly from the ketones by adding bromine, without isolating the olefin intermediates. Therefore, 1,2-dibromides can be easily synthesized, even via volatile olefins that are difficult to handle. Meanwhile, aliphatic ketones bordered by secondary alkyl groups, diaryl ketones, cyclic benzoyl ketones, and aryl methyl ketones yield only methylene compounds.