Palladium-Catalyzed Intramolecular 5-exo-dig Hydroarylations of N-Arylpropiolamides: Thermodynamics-Controlled Stereoselective Synthesis of 3-Methyleneoxindoles

Palladium-catalyzed intramolecular hydroarylation of N-arylpropiolamides has been developed for the stereoselective synthesis of 3-(monosubstituted methylene)oxindoles. In the presence of Pd(OAc)(2) and dppf, a variety of N-arylpropiolamides successfully underwent the intramolecular hydroarylation reaction to afford the corresponding 3-(monosubstituted-methylene)oxindoles in moderate to excellent yields. It is noteworthy that the stereoselectivity of the reaction can be controlled by varying the reaction temperature.