紫杉醇的半合成

以红豆杉属植物枝叶中含量丰富且易于提取的10-去乙酰-bacatinII(I)为原料,通过区域选择性反应得到被保护的紫杉醇母核;以α-甲基-苯甲胺为Staudinger反应的手性辅助剂,经7步反应合成了被保护的紫杉醇侧链(4S,5R)-N-(叔丁氧甲酰基)-2,2-二甲基-4-苯基-1,3-氧氮杂环戊烷-5-甲酸(X);以DCC为缩合剂连接侧链与母核,进而成功地半合成得到紫杉醇(I)。该途径可能是缓解紫杉醇供应危机的可行手段之一。

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.