Photoinduced site-selective alkenylation of alkanes and aldehydes with aryl alkenes
Hui Cao, Yulong Kuang, Xiangcheng Shi, Koi Lin Wong, Boon Beng Tan, Jeric Mun Chung Kwan, Xiaogang Liu, Jie Wu
Abstract
The dehydrogenative alkenylation of C-H bonds with alkenes represents an atom- and step-economical approach for olefin synthesis and molecular editing. Site-selective alkenylation of alkanes and aldehydes with the C-H substrate as the limiting reagent holds significant synthetic value. We herein report a photocatalytic method for the direct alkenylation of alkanes and aldehydes with aryl alkenes in the absence of any external oxidant. A diverse range of commodity feedstocks and pharmaceutical compounds are smoothly alkenylated in useful yields with the C-H partner as the limiting reagent. The late-stage alkenylation of complex molecules occurs with high levels of site selectivity for sterically accessible and electron-rich C-H bonds. This strategy relies on the synergistic combination of direct hydrogen atom transfer photocatalysis with cobaloxime-mediated hydrogen-evolution cross-coupling, which promises to inspire additional perspectives for selective C-H functionalizations in a green manner.