Copper‐Free Oxime–Palladacycle‐Catalyzed Sonogashira Alkynylation of Deactivated Aryl Bromides and Chlorides in Water under Microwave Irradiation

Abstract

Abstract Palladium‐catalyzed Heck alkynylation cross‐coupling reactions between terminal alkynes and deactivated aryl chlorides and aryl bromides can be performed in the absence of copper cocatalyst with water as solvent at 130 °C under microwave irradiation. An oxime‐derived chloro‐bridged palladacycle is an efficient precatalyst for this transformation with 2‐dicyclohexylphosphanyl‐2′,4′,6′‐triisopropylbiphenyl (XPhos) as ancillary ligand, pyrrolidine as base, and SBDS as surfactant. All of the reactions can be performed under air and with reagent‐grade chemicals under low loading conditions (0.1–1 mol‐% Pd).