Copper/Palladium Bimetallic System for the Synthesis of Isobenzofuranones through [4 + 1] Annulation between Propiophenones and Benzoic Acids

Abstract

A copper/palladium-catalyzed annulation from benzoic acids and propiophenones for the synthesis of isobenzofuranones was reported. The Cu-(2,2,6,6-tetramethylpiperidin-1-yl)oxyl system showed a great ability to activate the C–H bond on the α- and β-carbons of a carbonyl group, and the in situ-generated enone intermediate in this reaction could be further transformed to construct isobenzofuranones with the catalysis of Pd(dba)2 (dba = dibenzylideneacetone). Various isobenzofuranones could be obtained in moderate to good yields, and a great atom economy was highlighted by utilizing this method.