Application of a Stereospecific Intramolecular Allenylsilane Imino Ene Reaction to Enantioselective Total Synthesis of the 5,11-Methanomorphanthridine Class of <i>Amaryllidaceae</i> Alkaloids
作者:Jian Jin、Steven M. Weinreb
DOI:10.1021/ja970839n
日期:1997.6.1
Enantioselective total syntheses of the pentacyclic 5,11-methanomorphanthridine Amaryllidaceae alkaloids (−)-montanine (1), (−)-coccinine (2), and (−)-pancracine (3) were accomplished using an intramolecular concerted pericyclic allenylsilane imino ene cycloaddition as a key step. These complex natural products were constructed starting from readily available enantiomerically pure epoxy alcohol 15
五环 5,11-methanomorphanthridine Amaryllidaceae 生物碱 (-)-montanine (1)、(-)-coccinine (2) 和 (-)-pancracine (3) 的对映选择性全合成是使用分子内协调的周环丙二烯基硅烷亚胺烯完成的环加成是关键步骤。这些复杂的天然产物是从容易获得的对映异构纯环氧醇 15 开始构建的,通过有效的九步序列将其转化为丙二烯基硅烷醛 28。由醛 28 和亚氨基正膦 47 生成的亚胺经过立体有择的热亚亚胺烯反应,得到关键中间体顺式氨基炔烃 49。 可以通过 Lindlar 氢化和分子内 Heck 反应将该化合物转化为七元环四环 51。