Construction of Pyranoisoquinolines via Ru(II)-Catalyzed Unsymmetrical Double Annulation of N-Methoxybenzamides with Unactivated Alkynes

A ruthenium (Ru)-catalyzed double annulation of easily accessible N-methoxybenzamide derivatives with unactivated alkynes for the synthesis of unusual 6,6-fused pyranoisoquinolines is described. Both ortho-C–H bonds of arenes and the N- and O-moieties of N-methoxybenzamides are involved in the construction of four [(C–C)–(C–N) and (C–C)–(C–O)] bonds in one step under single catalytic conditions. The unsymmetrical annulation of...