Synthesis of β-hydroxysulfones through a copper(II)-catalyzed multicomponent reaction with the insertion of sulfur dioxide

A copper(ii)-catalyzed aerobic oxidative reaction of arylhydrazines, DABCO center dot(SO2)(2) and alkenes is reported. Diverse beta-hydroxysulfones are generated in moderate to good yields through the hydroxysulfonylation of alkenes with the insertion of sulfur dioxide under mild conditions. In some cases, beta-ketosulfones are produced, depending on the alkenes utilized. Arylhydrazines serve as the precursors of aryl radicals under aerobic atmosphere, which initiate the reaction. During the reaction process, aryl radicals react with sulfur dioxide leading to arylsulfonyl radicals, which subsequently undergo the hydroxysulfonylation of alkenes with oxygen to provide beta-hydroxysulfones and related compounds.