Synthesis of Azocine-Fused Indoles via Gold(I)-Catalyzed Cyclization of Azido-alkynes

Herein, we report a gold(I)-catalyzed cascade cyclization of azido-alkynes bearing an enol ester moiety, leading to indole-fused eight-membered rings. This method allows for the one-step construction of indole and tetrahydroazocin-4-one via an α-imino gold carbene intermediate. The resulting scaffold would be useful for accessing natural products with an eight-membered ring-fused indole moiety.