Pyranophane Transannular Diels−Alder Approach to (+)-Chatancin: A Biomimetic Asymmetric Total Synthesis
作者:Pierre Soucy、Alexandre L'Heureux、András Toró、Pierre Deslongchamps
DOI:10.1021/jo035193y
日期:2003.12.1
An asymmetric total synthesis of (+)-chatancin was achieved via a transannular Diels-Alder (TADA) reaction of an in situ generated macrocyclic pyranophane pseudobase. The presented route constitutes the second of two proposed biosynthetic pathways that involves a TADA reaction. It links this diterpene biogenetically to the cembranoids. A set of TADA selection rules that rationalize the formation of
通过原位生成的大环吡喃并pseudo假碱基的跨环Diels-Alder(TADA)反应,实现了(+)-茶霉素的不对称全合成。提出的途径构成了涉及TADA反应的两个拟议的生物合成途径中的第二个。它在生物上将二萜与大麻素联系起来。还概述了一组TADA选择规则,该规则合理地确定了从4个2-羟基-2H-吡喃自行车的动态平衡及其16个可能的TADA过渡态形成(+)-茶豆素的过程。除TADA反应外,合成工作的重点还包括从(S)-香茅醇中组装手性无环大环化底物,以及通过β-酮磺酰氧基/烯酮迈克尔加成反应进行有效的大环化。