Lewis Acid Mediated Vinylogous Additions of Enol Nucleophiles into an α,β-Unsaturated Platinum Carbene

A variety of substituted indoles and benzofurans are accessed via a platinum catalyzed annulation and vinylogous addition of enol nudeophiles. Several beta-dicarbonyl compounds participate in the reaction, as do alpha-nitro and alpha-cyano carbonyl species. Subjecting the indole products to acidic conditions results in the formation of fused heterocycles.