Ruthenium-catalyzed diyne hydrative cyclization: Synthesis of substituted 1,3-diene synthons

A novel and versatile strategy for the synthesis of highly functionalized substituted 3-sulfolenes based on [CpRu(CH3CN)31PF6-Catalyzed hydrative cyclization has been developed. A marked ketone directing effect in ruthenium-catalyzed cyclization was observed for the first time. This provides complementary chemoselectivity for the synthesis of 3-sulfolenes and other cyclic enones. The utility of this method has been demonstrated by SO2 extrusion of 3-sulfolenes to afford 1,3-dienes and the subsequent inter- and intramolecular Diels-Alder reaction.