Electrophotocatalytic oxygenation of multiple adjacent C-H bonds.

Abstract

Oxygen-containing functional groups are nearly ubiquitous in complex small molecules. The installation of multiple C-O bonds by the concurrent oxygenation of contiguous C-H bonds in a selective fashion would be highly desirable but has largely been the purview of biosynthesis. Multiple, concurrent C-H bond oxygenation reactions by synthetic means presents a challenge1-6, particularly because of the risk of overoxidation. Here we report the selective oxygenation of two or three contiguous C-H bonds by dehydrogenation and oxygenation, enabling the conversion of simple alkylarenes or trifluoroacetamides to their corresponding di- or triacetoxylates. The method achieves such transformations by the repeated operation of a potent oxidative catalyst, but under conditions that are sufficiently selective to avoid destructive overoxidation. These reactions are achieved using electrophotocatalysis7, a process that harnesses the energy of both light and electricity to promote chemical reactions. Notably, the judicious choice of acid allows for the selective synthesis of either di- or trioxygenated products.