Stereoselective Synthesis of Enamides by Palladium Catalyzed Coupling of Amides with Electron Deficient Olefins

A copper-free palladium-catalyzed convenient and efficient oxidative amidation protocol for synthesis of enamides by the cross-coupling of amides with acrylate has been developed. The thermodynamically disfavored Z-isomers are accessible by the intramolecular hydrogen bonding between the amido proton and carbonyl oxygen. The reactions were found to be acid catalyzed and p-TsOH gave the best result in enamide synthesis. The reactions were conducted at room temperature in presence of ambient air. This protocol has wide substrate scope allowing alkyl, aryl, substituted arylamides, urea, and its derivatives to react with methyl acrylate. The reactions are found to be tolerant to the steric demand of secondary amides and give the tertiary E-enamides in moderated to good yield.