Palladium-Catalyzed Serendipitous Synthesis of Arylglyoxylic Amides from Arylglyoxylates and ,-Dialkylamides in the Presence of Halopyridines.

A palladium-catalyzed synthesis of arylglyoxylic amides by the reaction of arylglyoxylates and ,-dialkylamides in the presence of a 2,3-dihalopyridine has been realized for the first time. An anticipated 2,3-diaroylpyridine did not form in this reaction. The current study unveils an unprecedented role of 2,3-dihalopyridine toward this amidation. Our mechanistic study reveals that the arylglyoxylate could react with halopyridine to form a traceless activated pyridyl ester of arylglyoxylic acid, which upon subsequent reaction with amino surrogate, ,-dialkylamides could form the arylglyoxylic amides.