PURPOSE: To produce an α,β-vinyl alcohol of a high optical purity by oxidizing an optically active sulfide into a sulfoxide with an oxidizing agent and then reacting the resultant sulfoxide with calcium carbonate.

CONSTITUTION: A solution containing an optically active sulfide of formula I (C* is asymmetric carbon; R1 is a 1-8C alkyl or an aromatic group; R2 is H, a 1-8C alkyl, an aromatic group, etc.; R3 to R5 are each H, a 1-8C alkyl or an aromatic group) dissolved in a solvent such as methanol is added to an oxidizing agent (e.g. sodium periodate) and the resultant mixture is then stirred at 0-100°C for 10-30hr to afford a sulfoxide. A solvent such as toluene is subsequently added to the sulfoxide and calcium carbonate and heated at 50-150°C under refluxing for 5-20hr to provide an optically active α,β-vinyl alcohol of formula II. The compound of formula II is useful for producing a synthetic intermediate for natural physiologically active substances or organic electronic materials such as a liquid crystal. Thereby, the asymmetric reduction of carbonyl group in the ω chain in a prostaglandin can efficiently be carried out in good asymmetric yield.