Highly Stereoselective Radical Cyclopropanation of Olefins via Cobaloxime-Based Metalloradical Catalysis

Metalloradical catalysis (MRC), predominantly exemplified by metalloporphyrin complexes, has emerged as a promising strategy for regulating radical reactions and broadening their synthetic applications. In this paper, we report that cobaloxime complexes, functioning as a surrogate for metalloporphyrin systems, can mediate radical cyclopropanation of olefins using donor/acceptor-type carbene precursor α-aryl diazoacetates through the MRC process. The reaction proceeds under mild conditions, yielding cyclopropane derivatives in good yields with high stereoselectivity. The reaction exhibits extensive substrate tolerance, encompassing gram-scale transformations and the synthesis of pharmaceutical compounds. Our discoveries underscore the potential of cobaloxime-catalyzed cyclopropanation as a valuable asset in organic syntheses and further expand the repertoire of metalloradical systems in catalysis.