An efficient, general method for the synthesis of 1,2-hydroxy esters by regioselective nucleophilic opening of 1,2-cyclic carbonate systems has been developed. A reliable and practical route giving access to the taxoid carbonate 2 from the readily available 10-deacetylbaccatin III (13) has been established. Nucleophilic opening of the carbonate 2 with a variety of nucleophiles provided a number of novel C-2 Taxols. Water-soluble taxoid onium salts (e.g., 31e, 31n, 32, and 34b) were also synthesized and studied. A selected number of taxoids were subjected to cytotoxicity and tubulin polymerization assays as well as in vivo studies. The results of these studies are reported herein.