PURPOSE: To prepare the subject compound in a short process and in a high yield by employing an inexpensive, readily available aldehyde derivative as a starting raw material, converting the derivative into an allylalcohol derivative, selectively epoxidizing the derivative, removing the protecting groups of OH groups and subsequently separating and purifying the objective compound.

CONSTITUTION: The diastereomer mixture of allyl alcohol derivatives of formulas I-IV (R1 is a hydroxyl group protected with an organic silyl group; R2 is lower alkyl) are subjected to an asymmetric epoxidization reaction to selectively epoxidize the diastereomers of formulas II and III. The protecting groups of the hydroxyl groups are removed and the optically active carbacycline derivative of formula V is separated and purified. The compounds of formulas I-IV are prepared by reacting a racemic aldehyde derivative of formula VI with an optically active withy reagent of formula VII (R3 is alkyl), protecting the hydroxyl group of the reaction product and subsequently reducing the prepared diastereo mixture of the enol compounds of formulas VIII and 1X. The compound of formula V is useful as an antiulcer agent, antiarteriosclerosis agent, angins pectoris treating agent, ischemic disease-preventing and treating agent, etc.