Dehydrogenation/(3+2) Cycloaddition of Saturated Aza-Heterocycles via Merging Organic Photoredox and Lewis Acid Catalysis

Teng-Fei Xiao, Yi-Fan Zhang, Wen-Tao Hou, Pen-Ji Yan, Jun Hai, Peng-Fei Xu*, and Guo-Qiang Xu*https://doi.org/10.1021/acs.orglett.1c03431

Abstract

Herein, we report a photoinduced dehydrogenation/(3+2) cycloaddition reaction by merging organic photoredox and Lewis acid catalysis, providing a straightforward and efficient approach for directly installing a benzofuran skeleton on the saturated aza-heterocycles. In this protocol, we also describe a novel organic photocatalyst (t-Bu-DCQ) with the advantages of a wider redox potential, easy synthesis, and a low price. Furthermore, the stepwise activation mechanism of dual C(sp3)–H bonds was demonstrated by a series of experimental and computational studies.