Palladium-Catalyzed Desymmetric [2+2+2] Cycloaddition Of 1,6-Enyne And Alkyne

A novel and straightforward palladium-catalyzed desymmetric [2+2+2] cycloaddition reaction of alkyne-tethered cyclohexadienone and internal alkyne is established. Widely existing fused tricyclic hydronaphthofuran and hydronaphthopyrrole frameworks are prepared diastereoselectively in moderate to excellent yields. One-step aromatization process provides a new and facile access to important benzene-containing tricycles from above cycloaddition products. (C) 2020 Elsevier Ltd. All rights reserved.