Ru-Catalyzed Decarbonylative Addition of Aliphatic Aldehydes to Terminal Alkynes

A novel method for the formation of isolated C=C bonds was developed via a ruthenium-catalyzed decarbonylative addition of aliphatic aldehydes and alkynes. An unprecedented complete switch of chemoselectivity from aromatic aldehydes to aliphatic aldehydes was observed simply by using tri(2,4,6-trismethoxyphenyl)phosphine as ligand. A synthesis by this method of an insect sex pheromone was demonstrated.