Synthesis of Aryl Ketones or Ketimines by Palladium-Catalyzed Arene C-H Addition to Nitriles

摘要

The unprecedented palladium-catalyzed C-H addition of arenes to nitriles provides moderate to excellent yields of aryl ketones or the corresponding hindered imines.The addition of a small amount of DMSO increases the yields dramatically.Both intermolecular and intramolecular reactions are successful,although the intramolecular reactions tend to be more sluggish.This novel chemistry is believed to involve palladium-catalyzed C-H activation of the arene by electrophilic aromatic substitution,followed by the unusual carbopalladation of a nitrile.Similar reactions have been successfully developed employing arylboronic acids and nitriles.A concise route to xanthones starting from cheap starting materials has been developed employing this synthetic protocol.