Total synthesis and absolute stereochemistry of polygalolides A and B
Total synthesis and absolute stereochemistry of polygalolides A and B
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DOI：
10.1002/anie.200602030
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发表时间：
2006-01-01
影响因子：
16.6
通讯作者：
Hashimoto, Shunichi
中科院分区：
文献类型：
--
作者：
Nakamura, Seiichi;Sugano, Yukihito;Hashimoto, Shunichi
2003年，Wei及其同事报道了从远志中获得的远志内酯A (1)和B (2)的分离和结构解析，远志是一种药用植物，其提取物在中国被用作补品和抗肝炎药物。 [1]根据核磁共振波谱数据确定了聚加酸内酯的结构和相对构型。然而，分子的绝对立体化学问题尚未得到解决。这些分子的结构复杂性，包括前所未有的三氧四环系统和位于 C2 和 C8 的连续四元立体中心，提出了相当大的合成挑战。在此，我们描述了 (À)-聚加仑内酯 A (1) 和 B (2) 的首次全合成。该合成利用了由串联羰基叶立德形成/1, 3-偶极环加成组成的转化，该转化已被广泛研究，特别是在
In 2003, Wei and co-workers reported the isolation and structural elucidation of the polygalolides A (1) and B (2) obtained from Polygala fallax Hemsl., a medicinal plant from which extracts are used as tonics and antihepatitis drugs in China.[1] The structure and relative configuration of the polygalolides were determined on the basis of NMR spectroscopic data. However, the issue of the absolute stereochemistry of the molecules has not been resolved. The structural complexity of these molecules, which include an unprecedented trioxatetracyclic ring system and contiguous quaternary stereogenic centers at C2 and C8, poses a considerable synthetic challenge. Herein, we describe the first total synthesis of (À)-polygalolides A (1) and B (2). The synthesis takes advantage of a transformation consisting of a tandem carbonyl ylide formation/1, 3-dipolar cycloaddition, which has been extensively studied, especially in the research group of