Electrochemical β-Scission-Mediated Ring Contraction/Functionalization of 2-Alkylidenecyclobutanol Derivatives

An electrochemical ring contraction/functionalization of 2-alkylidenecyclobutanol derivatives is presented, enabling the facile and oxidant-free synthesis of β-functionalized cyclopropanecarbaldehydes (CPAs) and cyclopropylketones (CPKs) though anodic oxidation, β-scission, and reoxidation processes. This protocol demonstrates a broad substrate scope, effectively accommodating a diverse range of 2-alkylidenecyclobutanols and various weak nucleophiles, thereby offering straightforward access to β-alkoxylated, hydroxylated, fluorinated, and azidated CPAs. Mechanistic investigations confirm the involvement of a 2-alkylidenecyclobutyl oxy radical intermediate and a subsequent β-scission process.