Exploration of a proposed biomimetic synthetic route to plumarellide. Development of a facile transannular Diels–Alder reaction from a macrocyclic enedione leading to a new 5,6,7-tricyclic ring system
作者:Yi Li、Gerald Pattenden
DOI:10.1016/j.tetlet.2010.10.154
日期:2011.4
A concise synthesis of the macrocyclic vinylbutenolide 19 is described, based on a facile RCM reaction of the substrates 16/18. Treatment of 19 with TFA containing water led to the 5,6,7-tricyclic compound 27, in a single step, in >90% yield, rather than to the alternative ring system 23 found in plumarellide (1). A rationale for the formation of 27 is presented, involving initial acid-catalysed hydrolysis
大环vinylbutenolide的简明合成19描述的基础上,基片的容易RCM反应16 / 18。用含有TFA的水处理19,一步得到5,6,7-三环化合物27,收率> 90%,而不是在Plumarellide(1)中发现另一种环系统23。提出了形成27的基本原理,涉及将呋喃甲醇中间体20初始酸催化水解为呋喃酮鎓离子21,然后将其水解为烯醇醚环状半缩酮22。中级22经历快速的互变异构化和异构化反应,生成二烯二酮24,然后参与环过Diels-Alder环化成26。26的脱水最终产生三环化合物27。