bis(camphanate) esters. The absolute configuration of bis(camphanate) ester (-)-8b was determined to be (aR) by X-ray analysis. The ester (aR)-(-)-8b was converted to the natural biflavone [CD(+)362.0]-(-)-1, leading to the (aR) absolute configuration of 1. This conclusion is consistent with our previous theoretical determination of the absolute stereochemistry of biflavone 1 by the molecular orbital calculation
已实现了天然阻转异构体4',4“',7,7”-四-O-甲基cu草
黄酮(1)的全合成。通过固态
苯酚偶联反应合成了关键中间体3,3'-
二乙酰基-4,4',6,6'-四甲氧基-2,2'-
联苯二醇(5),外消旋体5被拆分为双(
樟脑酸酯)酯。通过X射线分析确定双(
樟脑酸酯)酯(-)-8b的绝对构型为(aR)。酯(aR)-(-)-8b被转化为天然双
黄酮[CD(+)362.0]-(-)-1,导致(aR)的绝对构型为1。该结论与我们先前的理论相符CD光谱的分子轨道计算确定比
黄酮1的绝对立体
化学。