Directed Hydrozirconation of Homopropargylic Alcohols.

Homopropargylic alcohols undergo directed hydrozirconation with Schwartz reagent (Cp(2)ZrHCl) to generate vinyl-metal species in which the metal fragment is proximal to the alkoxide. Electrophilic trapping yields tri-substituted olefins in good yields with good control of regio- and stereochemistry. Experiments with a homopropargylic ether confirmed the role of the hydroxyl group in the directed hydrometalation.