Rhenium-Catalyzed Aryl-Acylcyclization between Enol Lactones and Organomagnesium Halides: Facile Synthesis of Indenones.

A set of rhenium-catalyzed aryl-acylcyclization between (hetero)arylmagnesium halides and enol lactones through a cascade Csp 2 -Csp 2 /Csp 2 -Csp 2 bond formation has been developed under mild reaction conditions. Indeed, a wide range of functional groups on both organomagnesium halides and enol lactones are well tolerated by the simple rhenium catalysis, thus furnishing polyfunctionalized indenones in one-pot fashion and with complete control of the regioselectivity. Moreover, this approach also provides a straightforward synthesis to neo-lignan and ( iso )pauciflorol F . Mechanistic studies demonstrated that the reaction involves a sequential of syn -carborhenation and intramolecular nucleophilic addition process.