Three-Component Cyclization/Haloazidation of Bicyclo[1.1.0]butane-1-carboxamides: Construction of Halogenated Spiro[cyclobutane-1,3′-quinolin]-2′-one Derivatives

A new BCB-type substrate to assemble halogenated spiro[cyclobutane-1,3'-quinolin]-2'-one derivatives via a radical cascade strain-release cyclization reaction has been successfully developed. The reaction features broad substrate scope, mild reaction conditions, and separated diastereomers. Importantly, the reaction time is very short (3-5 min), leading to this strategy being highly time-efficient and practical value.