Copper-catalyzed tandem A~3-coupling- isomerization-hydrolysis reactions of aldehydes and terminal alkynes leading to chalcones

摘要

Catalyzed by a simple copper salt, the reaction of an aryl aldehyde and a terminal alkyne in the presence of piperidine delivers the valuable chalcone products, which were rarely found in previous A~3 coupling reactions. This reaction can be applied to a wide range of substrates. Mechanistic studies indicate that this reaction experiences a tandem process containing A~3 coupling, copper assisted isomerization of propadienamine to allenylamine and subsequent hydrolysis.