The cyclopropane ring is a key motif in organic chemistry. The strained three-membered carbocycle is a structural feature in numerous drugs and fragrances, and serves as a versatile building block for complex molecule synthesis.

The novel method constitutes an advancement for the rapid synthesis of high-value cyclopropanes, as it can be performed under ambient conditions, including in the presence of air and moisture. Furthermore, its compatibility with continuous-flow technology enables scalability to multi-gram scales. Notably, the method enables access to methylated, deuterated, and chloro-substituted cyclopropanes using diverse feedstocks.

Abstract, as published with the paper

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.

Paper details

Morgan Regnier, Clara Vega, Dimitris I. Ioannou, Zhenyu Zhang, Timothy Noel: Flow Electroreductive Nickel-Catalyzed Cyclopropanation of Alkenes Using gem-Dichloroalkanes. Angew. Chem. Int. Ed. 2025, e202500203 DOI: 10.1002/anie.202500203

See also

Research group Flow Chemistry