2,3-Dihalo-1-propenes as Building Blocks in Cu(I)-Catalyzed Domino Reactions: Efficient and Selective Synthesis of Furans

Abstract

The Cu(I)-catalyzed reaction of 2,3-dibromo-1-propenes with β-ketoesters and 1,3-diketones, respectively, in DMF at 120 °C using Cs2CO3 as a base and hydroquinone as an additive exclusively delivers 2,3,5-trisubstituted furans and related compounds with yields up to 96%. The highly regioselective domino process is based on an intermolecular C-allylation followed by an intramolecular Ullmann type O-vinylation and a double bond isomerization.