Development of wide scope asymmetric synthesis of oxygen-bridged polycyclic compounds and its synthetic applications

Lewis酸催化重氮羰基化合物生成的环羰基酰的不对称环加成反应不仅以正电子需求型进行，而且以反电子需求型进行，如与乙烯醚和n -甲基吲哚的反应，具有高水平的不对称诱导。因此，开发了一种范围广泛的氧桥多环化合物的不对称合成方法。对于一般的重氮羰基底物，该方法不仅适用于含苯环的重氮化合物，也适用于无环重氮二酮和含吡咯烷环的底物。在合成应用方面，成功合成了(+)-Tashiromine。

Lewis acid catalyzed asymmetric cycloaddition reactions of cyclic carbonyl ylides generated from diazo carbonyl compounds were found to proceed not only by a normal electron demand type but also by an inverse electron demand type such as in the reaction with vinyl ethers and N-methylindoles with high levels of asymmetric induction. Thus a wide scope procedure for asymmetric syntheses of oxygen-bridged polycyclic compounds has been developed. With regard to a generality of diazo carbonyl substrates, the procedure could be applied for not only diazo compounds containing a benzene ring but also acyclic diazo diketones and the substrates containing a pyrrolidine ring. For the synthetic application, the synthesis of (+)-Tashiromine has been achieved.