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

reaction: see text]. A novel and versatile strategy for the synthesis of highly functionalized substituted 3-sulfolenes based on CpRu(CH3CN)3]PF6-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.