Ruthenium-catalyzed cascade C-H functionalization of phenylacetophenones.

Three orthogonal cascade CH functionalization processes are described, based on ruthenium-catalyzed CH alkenylation. 1-Indanones, indeno indenes, and indeno furanones were accessed through cascade pathways by using arylacetophenones as substrates under conditions of catalytic [{Ru(p-cymene)Cl-2}(2)] and stoichiometric Cu(OAc)(2). Each transformation uses CH functionalization methods to form CC bonds sequentially, with the indeno furanone synthesis featuring a CO bond formation as the terminating step. This work demonstrates the power of ruthenium-catalyzed alkenylation as a platform reaction to develop more complex transformations, with multiple CH functionalization steps taking place in a single operation to access novel carbocyclic structures.