Cu(I)-Catalyzed Coupling and Cycloisomerization of Diazo Compounds with Terminal Yne-Alkylidenecyclopropanes: Synthesis of Functionalized Cyclopenta[<i>b</i>]naphthalene Derivatives

A Cu­(I)-catalyzed coupling and cycloisomerization of diazo compounds with terminal yne-alkylidenecyclopropanes (ACPs) has been presented. This reaction starts from the formation of an allenic intermediate in the Cu­(I)-catalyzed cross-coupling reaction of a diazo compound with terminal alkyne in yne-tethered ACP and then undergoes a domino cycloisomerization of a 6π-electrocyclization and cyclopropane ring-opening rearrangement to give functionalized cyclopenta­[<i>b</i>]­naphthalene derivatives in moderate to excellent yields under mild conditions