Double Hydroamination of Alkyne via PTC and Microwave‐activated Diastereoselective Synthesis of 2,3‐dihydroimidazo[1,2‐a]pyridine2,3‐dihydroimidazo[1,2‐a]pyridine in an Aqueous Media

摘要

>A novel facile and diastereoselective synthesis of imidazopyridine with high atom economy in water as a green solvent under synergic effect of microwave activation and phase transfer catalysis from readily available 2‐aminopyridine and electrophilic alkyne, dimethyl acetylene dicarboxylate has been developed. The strategy of the protocol involves heterocyclisation via double hydroamination of dimethyl acetylene dicarboxylate in biphasic system catalyzed by benzyltriethylammonium bromide activated by microwave irradiation. The transformation proceeded smoothly and quantitatively at an ambient temperature. The reaction sequence of the protocol was also proved by electrochemical synthesis of imidazopyridine using same starting materials under similar reaction conditions.