One molar equivalent of dienols reacted with two molar equivalents of hydrozir-conation reagent (π-C₅H₅)a Zr(H)Cl (1) at room temperature afforded two stepwise reactions.1) The conversion of hydroxyl group to -O[Zr][[Zr]=(π-C₅H₅) a ZrCl-] by reacting with the first molar equivalent of 1.2) The locoselective addition of the second molar equivalent of 1 to the double bond remote from the hydroxyl group (the hydrozirconation reaction) forming the unsaturated organozirconinm complex.The structure of the complex was proved by ¹H NMR.Treatment of the complex with mineral acid produced alkenyl alcohol.Thus, the double bond remote from the hydroxyl group in the parent dienol was reduced by hydrozirconation.The selectivity of the hydrozirconation of dienols is 100%,e.g., hydrozirconation of 1, 7,-octadien-3-ol gave 1-octen-3-of as the sole product.Our xesnlts provided a new method of locoseleotive reduction of dienols.The high locoselectivity of hydrozirconation of dienols may be due to the sterio hindrance of the bulky -O[Zr] group, or more likely, due to the coordination of coordinatively unsaturated Zr atom of the -O(Zr) group to the neighbouring double bond, thus protected it from further addition reaction.When the dienola were allowed to react with one molar equivalent of hydroziroonation reagent at room temperature, organoziroonium complexes were formed with evolution of hydrogen.Treatment of the complex with mineral acid gave the starting alcohol, when the dienols were allowed to react with three molar equivalents.of hydrozirconation reagent, both saturated alcohol and alkenol were formed.