Vicinal Difunctionalization of Alkenes With Ketones and 1,2‐Bis(phenylsulfonyl)ethylene With One‐Electron Oxidation: A Three‐Component Route to Functionalized Vinyl Sulfones

Protocols for three‐component coupling reactions of ketones, alkenes, and 1,2‐bis(phenylsulfonyl)ethylene (BPSE) have been developed using one‐electron oxidizing systems based on potassium persulfate and manganese(III) acetate. These methods enable vicinal difunctionalization of alkenes, affording keto‐functionalized alkenyl sulfones in good to high yields. The reaction cascade is initiated by oxidative deprotonation of ketones via their enol forms. The resulting α‐keto radicals add to alkenes to generate alkyl radicals, which subsequently undergo an addition/β‐elimination sequence with BPSE, delivering the corresponding keto‐functionalized alkenyl sulfones in good yields. While persulfate is effective for generating α‐keto radicals from β‐diketones, manganese(III) acetate exhibits broader applicability, accommodating a wider range of mono‐ketones and protic C(sp 3 )‐H substrates. To gain insight into the observed preference for unactivated alkene addition over BPSE, DFT calculations were performed.