Regiocontrolled Benzannulation of Diaryl(<i>gem</i>-dichlorocyclopropyl)methanols for the Synthesis of Unsymmetrically Substituted α-Arylnaphthalenes: Application to Total Synthesis of Natural Lignan Lactones
作者:Yoshinori Nishii、Taichi Yoshida、Hirofumi Asano、Kazunori Wakasugi、Jun-ichi Morita、Yoshifumi Aso、Eri Yoshida、Jiro Motoyoshiya、Hiromu Aoyama、Yoo Tanabe
DOI:10.1021/jo047751u
日期:2005.4.1
synthesis of highly substituted α-arylnaphthalene analogues has been developed utilizing Lewis acid-promoted regiocontrolled benzannulation of aryl(aryl‘)-2,2-dichlorocyclopropylmethanols (aryl ≠ aryl‘; abbreviated as AACMs). Both AACM diastereomers were easily prepared via highly stereoselective addition (>95/5) of ArLi to gem-dichlorocyclopropropyl aryl‘ ketones. The choice of Lewis acids determined
利用路易斯酸促进的芳基(芳基)-2,2-二氯环丙基甲醇(芳基≠芳基;缩写为AACMs)的路易斯酸区域控制的苯环已开发出高取代的α-芳基萘类似物的有效合成方法。两种AACM非对映异构体都可以通过将ArLi高度立体选择性地加成(> 95/5)到宝石-dichlorocyclopropropyl aryl'ketones上来制备。路易斯酸的选择决定了本苯并环的环化区域选择性。TiCl 4和SnCl 4使用螯合途径,而甲硅烷基三氟甲磺酸盐使用非螯合途径以40-91%的产率提供不对称取代的区域异构α-芳基萘,具有中等至出色的区域选择性(TiCl 4或SnCl 4 ; > 99 / 1-3 / 1,TBDMSOTf;> 1 / 99-1 / 4)。因此,通过选择反应顺序的顺序或合适的催化剂,可将α-芳基或α-芳基'部分(辅助芳基)引入α-芳基萘。证明了本方法在不对称取代的天然木脂素内酯,justicidin