The dictyostatins are powerful microtubule-stabilizing agents that have shown antiproliferative activity against a variety of human cancer cell lines. Two highly active analogs of dictyostatin, 25,26-dihydrodictyostatin and 25,26-dihydro-6-epi-dictyostatin, were prepared by a new streamlined total synthesis route. Three complete carbon fragments were prepared to achieve maximum convergency. These were coupled by a Horner–Wadsworth–Emmons reaction sequence and an esterification. A late stage Nozaki–Hiyama–Kishi reaction was then used to form the 22-membered macrolide. The stereoselectivity of this reaction depended on the configurations of the nearby stereocenter at C6.
dictyostatins是一类强效的微管稳定剂,已显示出对多种人类癌细胞系的抗增殖活性。dictyostatin的两个高活性类似物,25,26-二氢dictyostatin和25,26-二氢-6-epi-dictyostatin,通过一条新的简化全合成路线制备。为了实现最大的汇聚性,制备了三个完整的碳片段。这些碳片段通过Horner–Wadsworth–Emmons反应序列和酯化反应耦合。然后使用晚期Nozaki–Hiyama–Kishi反应形成22-元大环内酯。这种反应的立体选择性取决于C6附近立体中心的构型。