Department of Chemistry, Brandeis University , MS 015, Waltham, Massachusetts 02454-9110, United States.
J Org Chem. 2013 Dec 6;78(23):12161-75. doi: 10.1021/jo402178r. Epub 2013 Nov 21.
A short and efficient synthesis of model spiroiminals that have the same stereochemistry as marineosins A and B, but different conformations, was carried out in six or seven steps from 6-methyltetrahydropyran-2-one. These spiroiminals were also prepared biomimetically by reduction of an enol ether. A more highly substituted spiroiminal with the same stereochemistry and conformation as marineosin A was prepared in 11 steps from parasorbic acid. A macrocyclic pyrrole lactone was prepared stereospecifically in 10 steps. A five-step sequence converted the lactone to a late hemi-iminal intermediate that has resisted the methylation and spiroiminal formation that would lead to marineosin A.
从 6-甲基四氢吡喃-2-酮出发，经六至七步反应，以中等总收率合成了与海洋霉素 A 和 B 具有相同立体化学而构象不同的模型螺环亚胺。这些螺环亚胺也可以通过烯醇醚的还原来生物模拟合成。用对伞花酸经 11 步反应以中等总收率合成了与海洋霉素 A 具有相同立体化学和构象的取代程度更高的螺环亚胺。用立体专一的 10 步反应合成了一个大环吡咯内酰胺。通过五步反应将内酰胺转化为一个半亚胺中间体，该中间体阻止了进一步的甲基化和螺环亚胺化反应，从而生成海洋霉素 A。
