Strategy for the Synthesis of Epoxide- and Carbonate-Containing Dienediyne Models of the Neocarzinostatin Chromophore – Application to the 6-Ring/11-Ring Case[1]
作者:Matthias Eckhardt、Reinhard Brückner
DOI:10.1002/jlac.199719970526
日期:1997.5
A novel synthetic strategy leading to bicyclic dienediyne models of the chromophore 1 of the anti-tumor antibiotic neocarzinostatin is described. Its key step is a ring-closing McMurry reaction of the dienediyne keto aldehydes 17 or 23. It leads to dienediynediols (compounds 19 and 24, respectively) or to trienediynes (compounds 18 and 25, respectively). Low temperatures favor the formation of dienediynediols
描述了导致抗肿瘤抗生素新carcarinostatin的发色团1的双环二烯二炔模型的新型合成策略。它的关键步骤是二烯二酮酮醛17或23的闭环McMurry反应。它导致二烯二炔二醇(分别为化合物19和24)或三烯二炔(分别为化合物18和25)。低温有利于二烯二炔的形成,而高温有利于二烯二炔的形成,因此酮醛23的McMurry反应显示出几乎完美的温度依赖性化学选择性(方案6)。Trienediyne 25含有一个缩酮基团,该缩酮基团被酸催化的甲醇分解作用除去(方案8)。将所得的二醇31单叔丁基甲硅烷基化以提供烯丙醇36(方案10)。用Sharpless的不对称环氧化试剂对它进行区域和立体选择性环氧化。将得到的环氧化物37转化成dienediyne epoxycarbonate顺- 33在共计七个步骤和5%的产率从bistriflate启动序列的最后步骤3b中; 3b本身可以分两个步骤从2-甲酰