6]-tetracyclic core framework that exhibit a broad spectrum of biological activities. A synthesis of the common core of epicoccolide A and epicocconigrone A has been achieved using an umpolung alkylation–lactonization to assemble an isochromanone from which the bridged 1,3-dioxane was readily assembled. A different strategy was required to access the core on the integrastatins; an initial aryllithium addition
整合抑制素,表球菌内酯A和表球果甾酮A,是
天然产物,含有独特的[6.6.6.6]-四环核心骨架,表现出广泛的
生物活性。表二
环己内酯A和表
三环烯酮A的共同核心的合成已通过使用umpolung烷基化-内酯化组装异
色酮而完成,从中可以容易地组装桥接的1,3-
二恶烷。访问integrastatins的核心需要采取不同的策略;首先将芳基
锂加成醛,然后氧化并用酸处理掩蔽的二羟基酮,得到所需的核结构。