Synthesis and chiral HPLC analysis of the dibenzyltetrahydrofuran lignans, larreatricins, 8′-epi-larreatricins, 3,3′-didemethoxyverrucosins and meso-3,3′-didemethoxynectandrin B in the creosote bush (Larrea tridentata): evidence for regiospecific control of coupling
作者:Syed G. A. Moinuddin、Shojiro Hishiyama、Man-Ho Cho、Laurence B. Davin、Norman G. Lewis
DOI:10.1039/b302632a
日期:——
tridentata) lignans are linked via 8-8' bonds, with the simplest apparently being E-p-anol derived. Of the latter, four of the six theoretically possible diastereoisomers were isolated, namely (-)-larreatricin, (-)-8'-epi-larreatricin, meso-3,3'-didemethoxynectandrin B and the new compounds, (+)- and (-)-3,3'-didemethoxyverrucosins. Following synthesis of each in either racemic or meso form, and chiral HPLC
杂酚丛(Larrea tridentata)木脂素通过8-8'键连接,最简单的显然是由Ep-醇衍生的。在后者中,分离出六个理论上可能的非对映异构体中的四个,即(-)-larreatricin,(-)-8'-epi-larreatricin,meso-3,3'-didemethoxynectandrin B和新化合物(+)-和(-)-3,3'-二甲氧基维可可菌素。合成外消旋或内消旋形式的每种化合物后,外消旋体对映体的手性HPLC分离后,确定天然存在的(-)-larreatricin和(-)-8'-epi-larreatricin存在于92和98中分别对映体过量%,而3,3′-二甲氧基维鲁可星本质上是外消旋的,而3,3′-二甲氧基花胶苷B是内消旋形式。有证据表明,这些木脂素的形成是在区域特异性下发生的,而不是立体声选择的耦合控制。这与Ep-醇的漆酶催化的“随机”偶合在体外形成对比,后者产生相应