ASYMMETRIC PHOTOADDITION OF CHIRAL ALLENES

描述：在这份修订后的申请中，首席调查员 指出联烯的分子内光环加成反应 带齿和烯的是构建 立体化学复杂的多环结构中的碳-碳键。 他报告说，他观察到了不对称诱导 手性1，3-二取代的光环化和光加成反应 带有烯酮的烯，其中不对称性完全来自 丙二烯片段。他指出，根据这些结果，目标是 这项建议的主要内容是：(1)碳环烯丙酮和 以烯-香豆素为底物的分子内不对称 光环加成(2)，以发展详细的理解 这些转换的机制，并为 立体化学的预测(3)发展一个光学家族 具有可移除辅助取代基的活性1，3-二取代烯烃， (4)对映体选择性联烯-烯酮的应用 生物活性单宁合成中的光加成反应 芥子酸。据报道，灯盏花酸及其相关单宁 通过抑制小牛胸腺和胸腺显示出强大的抗肿瘤活性 人结肠腺癌拓扑异构酶I

DESCRIPTION: In this revised application, the principal investigator states that the intramolecular photocycloaddition reaction of allenes with enoates and enones is a powerful tool for the construction of carbon-carbon bonds in stereochemically complex, polycyclic structures. He reports the he has observed asymmetric induction in the photocyclization and photoaddition reactions of chiral 1,3-disubstituted allenes with an enone in which asymmetry is derived exclusively from the allene fragment. He notes that on the basis of these results, the aims of this proposal are (1) examination of carbocyclic allene-enones and allene-coumarins as substrates for the intramolecular, asymmetric photocycloaddition (2) to develop a detailed understanding of the mechanism of these transformations and develop a paradigm for the prediction of stereochemistry (3) to develop a family of optically active 1,3- disubstituted allenes with removable auxiliary substituents, and (4) the application of the enantioselective allene-enone photoaddition reaction to the synthesis of the biologically active tannin chebulic acid. It is reported that chebulic acid and related tannins exhibit potent antitumerogenic activity by inhibition of calf thymus and human colon adenocarcinoma topoisomerase I.