Ruthenium-catalyzed cascade C-H functionalization of phenylacetophenones

Abstract

Three orthogonal cascade C-H functionalization processes are described, based on ruthenium-catalyzed C-H 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)Cl2}2] and stoichiometric Cu(OAc) 2. Each transformation uses C-H functionalization methods to form C-C bonds sequentially, with the indeno furanone synthesis featuring a C-O 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 C-H functionalization steps taking place in a single operation to access novel carbocyclic structures. Carbon coupling cascade: Arylacetophenones react with Michael acceptors under ruthenium catalysis to set up triple and quadruple C-H functionalization pathways. Through choice of reaction conditions, novel indanone carbacycles, indeno indene carbacycles, and indeno furanone heterocycles can each be accessed in a single step. © 2014 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.