Department of Chemistry, The University of Connecticut, Storrs, Connecticut 06269-3060, USA.
J Org Chem. 2012 Sep 21;77(18):7883-90. doi: 10.1021/jo301048z. Epub 2012 Sep 5.
Laureatin, a metabolite of the red algae Laurencia nipponica, has shown potent activity as a mosquito larvicide. The two previously published syntheses of laureatin involved an initial preparation of the 8-membered cyclic ether, followed by formation of the oxetane ring. Our strategy was the reverse, i.e., to utilize an oxetane as the framework to construct the larger ring. During this work, attempted N-bromosuccinimide (NBS)-mediated cyclization of oxetane alcohol 17, prepared from readily accessible 2-methyleneoxetane 12, yielded epoxytetrahydrofuran 19 rather than the expected laureatin core. Further derivatization of 19 yielded trans fused bis-tetrahydrofuran 32. The synthesis of 19 and 32, as well as structural and stereochemical elucidation studies, are described.
拉醇，一种来自红藻尼氏仙菜的代谢物，已显示出作为一种杀蚊幼虫剂的强大活性。之前发表的两种拉醇合成方法都涉及 8 元环醚的初步制备，然后形成氧杂环丁烷环。我们的策略则相反，即利用氧杂环丁烷作为构建大环的框架。在这项工作中，尝试用 N-溴代琥珀酰亚胺（NBS）介导的氧杂环丁烷醇 17 的环化反应，该醇是由易得的 2-亚甲氧基氧杂环丁烷 12 制备的，得到的是环氧四氢呋喃 19，而不是预期的拉醇核心。19 的进一步衍生化得到反式稠合双四氢呋喃 32。描述了 19 和 32 的合成以及结构和立体化学阐明研究。
