A new and convenient method for one-pot synthesis of α-arylhydrazo-β-keto sulfones is developed via Cu (II)-catalyzed oxysulfonylation/diazenylation of alkenes. This four-component cascade reaction enables a series of α-arylhydrazo-β-keto sulfone derivatives accessed from readily available alkenes, sulfinates, and diazonium salts under aerobic conditions. Furthermore, the 3-sulfonyl cinnolin-4(1 H)-one skeleton is successfully constructed from the corresponding α-arylhydrazo-β-keto sulfone product under basic conditions.