droxyl compound of the formula (XX) ##STR26## wherein each symbol is as defined above, and the hydroxyl compound is reacted with a halogenating agent such as thionyl chloride, phosphorous oxychloride, phosphorous trichloride, phosphorus pentachloride or phosphorus tribromide, or with methanesulfonyl chloride or p-toluenesulfonyl chloride in the presence of an acid scavenger to give a corresponding