Synthetic Organic Electrochemistry

Manganese-Catalyzed Electrochemical Deconstructive Chlorination of Cycloalkanols via Alkoxy Radicals

Alkoxy radicals are highly transient species that exhibit diverse reactivity, including hydrogen atom transfer, addition to pi-systems and beta-scission processes. The generation of alkoxy radicals directly from aliphatic alcohols is challenging, partly due to the high dissociation energy of RO−H bonds (~105 kcal/mol).

A manganese-catalyzed electrochemical deconstructive chlorination of cycloalkanols has been developed. This electrochemical method provides access to alkoxy radicals from alcohols and exhibits a broad substrate scope, with various cyclopropanols and cyclobutanols converted into synthetically useful beta- and gamma-chlorinated ketones (40 examples). Furthermore, the combination of recirculating flow electrochemistry and continuous inline purification was employed to access products on gram scale (Org. Lett., 2019, 21, 9241-9246). [link]