Synthetic Study on Taxol.

紫杉醇因其高细胞毒性和较强的抗肿瘤活性而备受关注。社会对紫杉醇需求的增加促使我们建立紫杉醇的全合成方法。然而，紫杉醇的复杂结构阻碍了紫杉醇的有效途径。因此，开发更容易获得的紫杉醇类似物将在不久的将来。从这些方面出发，我们设计了一种高效、灵活的紫杉醇全合成方法。首先，外消旋A环合成子由2，2-二甲基-1，3-环己二酮经10步制备。第二步，以R-（-）-香芹酮为原料，经12步反应合成了C环合成子。由A环合成子生成的乙烯基阴离子与由C环合成子衍生的醛反应。然而，如此获得的B环前体的闭环尚未实现。

Paclitaxl has received much attention because of its high cytotoxicity and strong antitumor activity. An increased social demand for paclitaxl prompts us to establish a total synthetic method for paclitaxl. However, the complicated structure of paclitaxl obstructs an efficient route to paclitaxl. So, development of a more readily available paclitaxl analogues will be anticipated in the near future. From these points, we projected an efficient and flexible total synthetic method for paclitaxl. First, racemic A ring synthon was prepared in 10 steps from 2,2-dimethy1-1,3-cyclohexanedione. Second, C ring synthon was synthesized in 12 steps from R-(-)-carvone. A vinyl anion generated from A ring synthon was uneventfully reacted with an aldehyde derived from C ring synthon. However, ring closure of the B ring precursor thus obtained has not been realized yet.