Reduction of the keto function of pristinamycine IIB (I) with NaBH4 in the presence of HOAc afforded diol (II). The 14-hydroxy group of (II) was then selectively protected as the tert-butyldiphenylsilyl ether, yielding (III). Subsequent fluorination of the 16-hydroxyl of (III) was achieved by treatment with diethylaminosulfur trifluoride. Finally, deprotection of the resultant silyl ether (IV) was effected by means of tetrabutylammonium fluoride in THF. A closely related method was based on the protection of (II) as the 14-O-tert-butyldimethylsilyl derivative (V). After fluorination of (V) with diethylaminosulfur trifluoride, the resultant fluoro silyl compound (VI) was deprotected with triethylamine trihydrofluoride.

In an alternative procedure, diol (II) was selectively protected as the 14-allyl ether (VIII) by O-alkylation with allyl bromide (VII) in the presence of K2CO3. Displacement of the 16-hydroxyl of (VIII) with diethylaminosulfur trifluoride provided fluoride (IX). The O-allyl protecting group of (IX) was finally removed employing p-toluenesulfonic acid and palladium tetrakis(triphenylphosphine).