Abstract:2'-O-[4-N,N-dimethylamino-2(R)-fluoro-butyryl]-paclitaxel hydrochloride (Ⅵ) was synthesized from Bakatin III(Ⅰ) via acylation, condensation, selective deprotection and hydrogenolysis of 2'-O-[4-N,N-dimethylamino-2(R)-fluoro-butyryl]-7-O-benzyloxycarbonyl- paclitaxel hydrochloride (V), which was prepared by the esterification of 7-O-benzyloxycarbonyl -paclitaxel (Ⅳ) with (R)-4-N,N-dimethylamino-2-fluoro-butyryl chloride hydrochloride (Ⅶ). The effect of volume ratio of trifluoroacetic acid and acetic acid on reaction time during the preparation of compound IV, dosage of (R)-4-N,N-dimethylamino-2 -fluoro-butanoic acid hydrochloride (Ⅷ) and catalyst (4-DMAP) on Ⅳ conversion during the preparation of compound Ⅴ were investigated. The optimal conditions were as following: V (trifluoroacetic acid): V (acetic acid) = 1∶8; n (Ⅳ)∶n (4-DMAP)∶n (Ⅷ) = 1∶3∶3. The structure of target product was confirmed by MS, 1HNMR and 13CNMR. The synthesis process was simple, overall yield was more than 60%, and the purity of the target product was 99% (HPLC).