Flow Electroreductive Nickel-Catalyzed Cyclopropanation of Alkenes Using gem-Dichloroalkanes.

Cyclopropanes are valuable motifs in organic synthesis, widely featured in pharmaceuticals and functional materials. Herein, we report an efficient electrochemical methodology for the cyclopropanation of alkenes, leveraging a nickel-catalyzed process in continuous-flow. The developed protocol demonstrates broad substrate scope, accommodating both electron-rich and electron-poor alkenes with high functional group tolerance. Beyond dichloromethane as a feedstock methylene source, the methodology enables the synthesis of methylated, deuterated, and chloro-substituted cyclopropanes. Mechanistic investigations suggest the electro-generation of a nickel carbene as key intermediate. Notably, the reaction operates under ambient conditions, tolerates air and moisture, and achieves scalability through continuous-flow technology, offering a straightforward route to multi-gram quantities with enhanced throughput.