Copper-Catalyzed Formal C(sp³)-H Insertions via 1,5-Diyne Cyclization Triggered by a 1,6-Hydride Shift

In recent decades, C(sp³)-H bond functionalization has emerged as an efficient strategy for the direct construction of C-C or carbon-heteroatom bonds. Herein, we report a copper-catalyzed cascade cyclization of 1,5-diynes involving formal C(sp³)-H insertions via a 1,6-hydride shift mediated by a γ-C-copper vinyl cation intermediate, enabling the atom-economical synthesis of various benzo[e]isoindoles under mild conditions. This C(sp³)-H insertion reaction exhibits a distinctive reaction mode in comparison with previous reports. Furthermore, preliminary studies on asymmetric catalysis have afforded the corresponding products with moderate enantioselectivity. Importantly, this protocol offers a novel avenue to realize C(sp³)-H bond functionalization based on vinyl cation intermediates.