New production of taxane using oxazolidine intermediate

PROBLEM TO BE SOLVED: To obtain a new oxazolidine compound useful as an intermediate for synthesizing 13C acyloxy side chain-bound taxanes having pharmacological activity, and to provide a method for producing taxanes by using the above intermediate. SOLUTION: A compound of formula I (R 1 is H, an arylcarbonyl, alkoxycarbonyl or the like; R 2 is an aryl, heterocycle or alkyl; R 5 and R 6 are each an alkyl or the like) or a salt thereof is brought into contact with (B) a compound of the formula: HO-T (T is a taxane moiety directly bound to its C 13 site) or a salt thereof to form (C) a compound of formula II or a salt thereof, which, in turn, is brought into contact with a ring-opening agent (pref. a Lewis acid) followed by, if necessary, deprotection of the protected hydroxyl group to obtain (D) the objective compound of formula III or a salt thereof. By the way, the compound of formula I where R 1 is R 1 * is prepared by bringing a compound of formula IV (R 4 is an alkyl, alkenyl, aryl or the like; R 1 * is H, an arylcarbonyl or the like) into contact with a hydrolyzing agent. COPYRIGHT: (C)1996,JPO