Efficient synthesis of dolastatin 15 (1) was accomplished following a convergent strategy. The pyrrolidinone cycle of 5 was obtained by thermic cyclization of the corresponding Meldrum's adduct 4. The methylation of the enol function was performed under Mitsunobu conditions. On the other hand, the peptide part 10 was elongated by using PyCloP as coupling reagent. The ester linkage between both segments was efficiently performed under conditions we previously described by using a mixed anhydride activation with isopropenyl chlorocarbonate. Final compound 12 was found to exhibit physical properties slightly different from those recently reported by Pettit and co-workers for the natural dolastatin 15 and their synthesis product.

中文翻译：

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Dolastatin 15拟议结构的全合成

遵循收敛策略，完成了dolastatin 15（1）的高效合成。通过相应的Meldrum加合物4的热环化获得5的吡咯烷酮循环。在Mitsunobu条件下进行烯醇功能的甲基化。另一方面，通过使用PyCloP作为偶联剂来拉长肽部分10。两个链段之间的酯键是在我们先前描述的条件下通过使用异丙烯基氯碳酸酯进行混合酸酐活化而有效地进行的。最终化合物12 发现其物理性质与Pettit及其同事最近报道的天然dolastatin 15及其合成产品的物理性质略有不同。