Palladium-Catalyzed Reactions of Enol Ethers: Access to Enals, Furans, and Dihydrofurans

The palladium-catalyzed oxidation of alkyl enol ethers to enals, which employs low loadings of a palladium catalyst, is described. The mild oxidation conditions tolerate a diverse array of functional groups, while allowing the formation of di-, tri-, and tetrasubtituted olefins. The application of this methodology to intramolecular reactions of alkyl enol ethers containing pendant alcohols provides furan and 2,5-dihydrofuran products.