SEMISYNTHESIS OF TAxoL

Taxol is current ly one of the most important cancer chemotherape ut ic agents.HOwever, the large-scale clinical usage of taxol has been hampered by its limited supply.The dilemmacan be partly resolved by semisynthesis from inactive but abundant taxanes obtained frOm the leavesand stems of various Taxus species which can be harvested without destroying the trees. In thispaper, protected baccatin IIl was obtained using l0-deacetyl baccatin IIl which is abundant in theleaves and stems of Taxus plants as starting material by regioselective synthesis. The prOtected taxolside chain(4S, 5R)-N-Boc-2,2-dimethyl-4-phenyl-5-oxazOlidinecarbOxylic acid was prepared by usingamethyL-benzylamine as the chiraI template of a Staudinger reaction. Taxol was successfully generatedby union of the two parts,deprotection and N-benzoylation.