Transition-Metal-Catalyzed Propargylic Substitution of Propargylic Alcohol Derivatives Bearing an Internal Alkyne Group

The development of the transition-metal-catalyzed propargylic substitution of propargylic alcohol derivatives is one of the active research subjects in organic synthesis. In this minireview, we summarize the catalytic propargylic substitution of propargylic alcohol derivatives bearing an internal alkyne group using a transition metal as the catalyst. Although the asymmetric propargylic substitution of the substrate class still underdeveloped, some transition metal catalyses using nickel, palladium, and copper, and the cooperative catalysis enabled the challenging transformation. A various types of transition-metal catalysts are known to promote the non-asymmetric propargylic substitution of the internal alkyne-substituted propargylic alcohol derivatives via a propargylic cation intermediate, realizing the carbon-carbon and carbon-heteroatom bond formation at the propargylic position.