solvent at 10 to 30 u00b0 c preferably 15 to 25 u00b0 c for 1 to 3 hrs and examples of the organic solvent include dichloromethane tetrahydrofuran dimethylformamide and a mixture thereof after completion of the reaction the reacting mixture is crystallized from a solvent such as hexane ethyl acetate and a mixture thereof at u2212 10 to 0 u00b0 c to obtain the cyclopentene compound of formula 10 as a solid alternatively in case that r 1 and r 2 are fused together to form e g naphthylidene the protecting group of the chiral cyclopentenol compound of formula 9 obtained in step 1 is removed to obtain the corresponding cyclopentenediol which is treated with carbonyl or alcohol derivatives in the presence of an acid catalyst to obtain the cyclopentene compound of formula 10 examples of the acid catalyst are pyridinium p toluenesulfonate p toluenesulfonic acid and a mixture thereof and the amount of the acid catalyst is preferably 0 1 to 0 3 molar equivalents examples of the carbonyl derivative are naphthylaldehyde naphthylaldehyde dimethylacetal benzaldehyde benzaldehyde dimethylacetal 4 phenylbenzaldehyde 4 phenylbenzaldehyde dimethylacetal and a mixture thereof and example of the alcohol derivative is dimethoxypropane the cyclopentanol compound of formula 11 is prepared by treating the cyclopentene compound of formula 10 obtained in.