A Reagent-Controlled Divergent Route to Pyranone Scaffolds via Formal Insertion of Vinyl Sulfoxonium Ylides into Activated Alkenes

Abstract A reagent-controlled divergent reaction of vinyl sulfoxonium ylides with arylideneindane-1,3-diones has been developed. The transformation proceeds through in situ formation and selective cleavage of donor–acceptor cyclopropane intermediates, providing dihydropyranone and indenopyranone scaffolds with excellent regio- and stereoselectivity. B(C6F5)3 affords dihydropyranones, whereas ceric ammonium nitrate (CAN) furnishes indenopyranones. Mechanistic studies identify a common vinyl cyclopropane intermediate and support distinct ionic and radical pathways.