Suman Ghosh, Partha Saha, Mainak Koner, Shabbir Ahmed Khan, Manoj V. Mane, Mahiuddin Baidya
We report the first Ru(II)-catalyzed annulative linear dienylation reaction of aromatic amides with allenyl carbinol acetates. The protocol capitalizes on an oxidizing directing group and leverages regioselective 1,2-insertion of the allene motif to afford valuable 3-styrylisoquinolinones in high yields with exclusive trans -olefin geometry. It is operationally simple and scalable, features a wide substrate generality, and also remains effective in the presence of medicinally relevant scaffolds. The products can be further transformed into π-extended tetracyclic pyrano[2,3,4- gh ]phenanthridines, which serve as efficient photocatalysts for reductive coupling reactions, as demonstrated by dehalogenative phenanthridinone formation and reductive pinacol coupling. DFT studies were carried out to elucidate the reaction mechanism and the origin of the observed selectivity.