Natural Furanocembranoids. A Synthetic Approach to Lophotoxin based on an Acyl Radical Macrocyclisation Strategy
作者:Martin P. Astley、Gerald Pattenden
DOI:10.1055/s-1992-34169
日期:——
A concise synthesis of the furan-containing macrocyclic (cembranoid) ring system 8 (10-isopropenyl-3,7,13-trimethyl-15-oxabicyclo [10.2.1]pentadeca-2,6, 12,14-tetraene) found in Iophotoxin (1) and other members of this family of irreversible nicotinic receptor antagonists, is described. The synthesis features a 14-endo trig cyclisation from an unsaturated acyl radical intermediate incorporating a terminal conjugated enone moiety, viz 10, leading to the macrocycle (5E,9E)-13-isopropenyl-2,6,10-trimethylcyclotetradeca-5, 9-diene-2,4-dione (9), followed by acid-catalysed furan ring formation from the resulting 1,4-dione system in 9 (Scheme 1).
本文描述了一种含呋喃的大环(cembranoid)环系统 8(10-异丙烯基-3,7,13-三甲基-15-氧杂双环[10.2.1]戊十-2,6,12,14-四烯)的简明合成方法,该系统存在于 Iophotoxin (1) 和该不可逆烟碱受体拮抗剂家族的其他成员中。该合成方法的特点是,先从含有末端共轭烯酮分子(即 10)的不饱和酰基中间体进行 14- 内向三环化反应,生成大环 (5E,9E)-13-异丙烯基-2,6,10-三甲基环十四碳-5,9-二烯-2,4-二酮 (9),然后在酸催化下从 9 中生成的 1,4- 二酮体系中形成呋喃环(方案 1)。