Visible-light-mediated cobaloxime-catalyzed isomerization and hydroalkenylation of bicyclo[1.1.0]butanes†

Bicyclo[1.1.0]butanes have received extensive attention from chemists in recent years and diverse approaches to access transformations of such strained molecules have been explored. Although cobalt catalysis has become a promising field in organic synthesis, the cobalt-catalyzed strain-release strategy of bicyclobutanes is still underdeveloped. Herein, we disclose a visible-light-driven cobaloxime-catalyzed protocol for bicyclo[1.1.0]butane transformations. A range of cyclobutene and alkenylated cyclobutane products have been obtained in moderate to excellent yields with excellent functional group tolerance. Synthetic applications of this protocol were conducted with several transformations. Moreover, a series of control experiments and spectroscopic experiments were performed to demonstrate the reaction mechanism.