Cationic Pd(II)-Catalyzed Reductive Cyclization of Alkyne-Tethered Ketones or Aldehydes Using Ethanol as Hydrogen Source

A cationic Pd(II)-catalyzed reductive cyclization of alkyne-tethered ketones or aldehydes using ethanol as hydrogen source under mild conditions was developed. The reaction is an environmentally benign synthetic method and proceeds efficiently to give useful N-heterocycles or carbocycles bearing an exocyclic double bond and a hydroxyl group in high yield.