Silver‐Catalyzed and Base‐Mediated Double Cyclization for the Streamlined Synthesis of Benzo[4,5]imidazo[2,1‐b]naphtho[2,3‐d]oxazole from ortho‐Alkynylarylketones

We report a novel silver‐catalyzed and base‐mediated double cyclization strategy for the streamlined synthesis of benzo[4,5]imidazo[2,1‐b]naphtho[2,3‐d]oxazoles from ortho‐alkynylarylketones. The transformation proceeds through an initial ketonization step catalyzed by silver trifluoroacetate (AgTFA), generating a reactive 1,5‐diketone intermediate, followed by a sequential double cyclization under basic conditions. This method affords a broad range of benzo[4,5]imidazo[2,1‐b]naphtho[2,3‐d]oxazoles with good functional group tolerance in moderate to good yields. Moreover, this methodology also enhances the synthetic utility of ortho‐alkynylarylketones, expanding their applicability in constructing diverse fused heterocycles.