Many first-line cancer drugs are natural products or are derived from them by chemical modification. The trioxacarcins are an emerging class of molecules of microbial origin with potent antiproliferative effects, which may derive from their ability to covalently modify duplex DNA. All trioxacarcins appear to be derivatives of a nonglycosylated natural product known as DC-45-A2. To explore the potential of the trioxacarcins for the development of small-molecule drugs and probes, we have designed a synthetic strategy toward the trioxacarcin scaffold that enables access to both the natural trioxacarcins and nonnatural structural variants. Here, we report a synthetic route to DC-45-A2 from a differentially protected precursor, which in turn is assembled in just six steps from three components of similar structural complexity. The brevity of the sequence arises from strict adherence to a plan in which strategic bond-pair constructions are staged at or near the end of the synthetic route.
许多一线癌症药物是天然产物或经过化学修饰得到的。三氧环菌素是一类新兴的微生物来源分子,具有强大的抗增殖作用,可能源于它们能够共价修饰双链DNA的能力。所有的三氧环菌素似乎都是一种非糖基化的天然产物DC-45-A2的衍生物。为了探索三氧环菌素作为小分子药物和探针的潜力,我们设计了一种合成策略,以便访问天然的三氧环菌素和非自然的结构变体。在这里,我们报道了从不同保护的前体合成DC-45-A2的方法,该前体仅需从三个结构复杂度相似的组分中经过六个步骤组装而成。这一序列的简洁性源于对计划的严格遵守,其中战略性的键对构造在合成路径的末端或附近进行分阶段。