Electrochemically driven cross-electrophile esterification of alkyl halides

Abstract

Electroreductive cross-electrophile coupling has emerged as a powerful and efficient method for constructing challenging C–C or C–X bonds, providing several advantages including highly efficient electron transfer, tunable reducing potential, direct electricity-activation of substrates and good scalability. In electroreductive cross-electrophile coupling, a high loading of a transition metal catalyst is required to facilitate the transfer of electrons from the cathode to organic halides, making it unsuitable for sensitive organic halides such as chloroformates. As a result, the electroreductive XEC of readily accessible chloroformates with alkyl halides for ester synthesis remains a largely unmet challenge. In this work, catalyst-free electrochemically driven cross-electrophile esterification of alkyl halides has been developed. A wide range of 2-phenylacetic esters which represent an important class of molecules in synthetic and medicinal chemistry are accessed from simple and cheap alkyl halides and alkyl chloroformates under mild reaction conditions. Various functional groups were well tolerated, affording up to 98% yields. This protocol would contribute a lot for the further development of electrochemically driven cross-electrophile coupling.