Brønsted Acid-Catalyzed Reactions of Vinylboronic Acids and Benzhydryl Alcohols

Abstract

The functionalization of benzhydryl alcohols is an approach to form important building blocks in organic synthesis. More specifically, the derivatization of benzhydryl alcohols to afford an alkene is a desired approach due to the wide variety of derivatizations applicable to 1,3,3-triphenylpropene derivatives. However, many approaches towards functionalization rely on harsh reaction conditions or the use of Lewis acid catalysts, which leads to low functional group tolerance. Herein, a methodology for the formation of 1,3,3-triphenylpropene derivatives through a Brønsted acid-catalyzed reaction of styrylboronic acids and benzhydryl alcohols is reported. The use of tetrafluoroboric acid diethyl ether complex (HBF4·OEt2) in substoichiometric amounts is desirable as it allows for the introduction of the desired alkene structural motif under less harsh conditions than the previously reported methodologies. Using milder reaction conditions results in a broader scope of benzhydryl alcohols and styrylboronic acids as starting materials.