Site-selective functionalization of Amphotericin B has been achieved by simply modifying the electronic nature of the reagents. A Hammett analysis is consistent with linking of this phenomenon to the Hammond postulate: electronic tuning to a more product- like transition state amplifies site-discriminating interactions between a reagent and its substrate. Electronic tuning of both an acylpyridinium donor and its carboxylate counterion further promoted site-divergent functionalization. A range of modifications to one of the many hydroxyl groups appended to the ion channel-forming natural product amphotericin B was achieved.
Amphotericin B的位选择性官能化已通过简单修改试剂的电子性质实现。 Hammett分析与将这一现象与Hammond假设联系起来是一致的:对更类似产物的过渡态进行电子调谐会增强试剂与其底物之间的区位区分相互作用。对酰基
吡啶阳离子供体及其
羧酸盐反离子的电子调谐进一步促进了位分歧官能化。对形成离子通道的
天然产物Amphotericin B之一的许多羟基基团的一系列修饰已实现。