Switchable Divergent Synthesis of Cyclopropane Scaffolds Enabled by Photoredox Catalytic Cascade.

Given the essential and valuable characteristics of cyclopropane scaffolds in pharmaceutical and organic chemistry, general strategies for their construction are highly desirable. However, the divergent synthesis of spirocyclopropanes and 1,1-substituted cyclopropanes using the same starting materials remains a challenge. Herein, we disclose a visible-light-promoted procedure for the concise and divergent construction of spirocyclopropyl succinimides (28 examples, yields up to 95%) and cyclopropyl-acetamides (18 examples, yields up to 82%) from N-substituted oxamic acids and methyl 4-chloro-2-methylenebutanoate by radical addition/polar crossover/cyclization/cyclization (RAPCC) and radical addition/polar cyclization (RAPC) cascades. The versatility and practicality of this photocatalytic approach are underscored by its good functional group tolerance and broad substrate scope, which include tolerating the valuable handles and late-stage modification of medicinal agents.