Synthesis of Polyprenylated Acylphloroglucinols Using Bridgehead Lithiation: The Total Synthesis of Racemic Clusianone and a Formal Synthesis of Racemic Garsubellin A
作者:Nadia M. Ahmad、Vincent Rodeschini、Nigel S. Simpkins、Simon E. Ward、Alexander J. Blake
DOI:10.1021/jo070388h
日期:2007.6.1
means of regioselective lithiation reactions, including the generation of bridgehead enolates, thus enabling the total synthesis of clusianone and also of an advanced intermediate toward nemorosone. In the case of garsubellin A, an additional THF-like ring was elaborated by a biomimetic 5-exo-tet cyclization of an enol ether (or enol) with a side-chain epoxide. This enabled a formal synthesis of racemic
聚异戊二烯化间苯三酚天然产物的合成,包括clusianone,nemorosone和garsubellin A,是通过以下策略进行合成的:构建双环[3.3.1] nonanetrione核心结构,然后通过有机锂中间体进行精制。通过适当取代的环己酮烯醇醚或烯醇硅烷与丙二酰二氯的环化反应,获得适当的桥连核心结构。然后通过区域选择性锂化反应引入额外的取代基,包括桥头烯醇酸酯的生成,从而实现了clusianone以及向nemorosone的高级中间体的全合成。对于Garsubellin A,通过仿生的5 -exo-tet修饰了另一个类似THF的环带有侧链环氧化物的烯醇醚(或烯醇)的环化。通过进入Danishefsky合成中的一种较晚的中间体,这使得外消旋garsubellin A的正式合成成为可能。