Electroreduction of unactivated alkenes using water as hydrogen source

Abstract

Herein, we report an electroreduction of unactivated alkyl alkenes enabled by [Fe]-H, which is provided through the combination of anodic iron salts and the silane generated in situ via cathodic reduction, using H₂O as an H-source. The catalytic amounts of Si-additive work as an H-carrier from H₂O to generate a highly active silane species in situ under continuous electrochemical conditions. This approach shows a broad substrate scope and good functional group compatibility. In addition to hydrogenation, the use of D₂O instead of H₂O provides the desired deuterated products in good yields with excellent D-incorporation (up to >99%). Further late-stage hydrogenation of complex molecules and drug derivatives demonstrate potential application in the pharmaceutical industry. Mechanistic studies are performed and provide support for the proposed mechanistic pathway.

The reduction of unactivated alkyl alkenes is a difficult challenge in organic chemistry. Here, the authors present a silicon-mediated electroreduction of alkyl alkenes, using water as a hydrogen source, enabled by [Fe]-H.