The protected glucuronic acid derivative (I) is hydrolyzed under alkaline conditions to furnish (II). The alcoholic hydroxyl groups of (II) are subsequently protected as the silyl ether (III) employing t-butyldimethylsilyl triflate in the presence of DMAP. The carboxyl group of (III) is further converted to the corresponding benzyl ester (IV) by DCC-mediated coupling with benzyl alcohol. Acylation of amine (IV) with phosgene leads to the carbamyl chloride (V). (1,2)

Reaction of etoposide (VI) with acid chloride (V) produces the carbamate adduct (VII). The silyl protecting groups of (VII) are then removed by treatment with HF-pyridine yielding triol (VIII). Finally, the benzyl ester function of (VIII) is deprotected by transfer hydrogenolysis in the presence of cyclohexadiene and Pd/C. (1,2)

The protected glucuronic acid derivative (I) is hydrolyzed under alkaline conditions to furnish (II). The alcoholic hydroxyl groups of (II) are subsequently protected as the silyl ether (III) employing t-butyldimethylsilyl triflate in the presence of DMAP. The carboxyl group of (III) is further converted to the corresponding benzyl ester (IV) by DCC-mediated coupling with benzyl alcohol. Acylation of amine (IV) with phosgene leads to the carbamyl chloride (V). (1,2)

Reaction of etoposide (VI) with acid chloride (V) produces the carbamate adduct (VII). The silyl protecting groups of (VII) are then removed by treatment with HF-pyridine yielding triol (VIII). Finally, the benzyl ester function of (VIII) is deprotected by transfer hydrogenolysis in the presence of cyclohexadiene and Pd/C. (1,2)