Sequential ruthenium-catalyzed hydroamination and rhenium-catalyzed C-H bond activation leading to indene derivatives

reaction: see text] Formal 3 + 2] annulation of arylacetylenes and alpha,beta-unsaturated carbonyl compounds is achieved in a one-pot reaction by successive treatment of the acetylenes with aniline and a catalytic amount of Ru(3)(CO)(12) and NH(4)PF(6) and C-H bond activation catalyzed by ReBr(CO)(3)(thf)](2). The result suggests that the second rhenium-catalyzed indene formation is not disturbed by the first catalyst system.