Towards a Total Synthesis of Quinocarcin: Diastereoselective Synthesis of Functionalized Azepino[1,2-b]isoquinolines
作者:Oliver Koepler、Sabine Laschat、Angelika Baro、Peter Fischer、Burkhard Miehlich、Marc Hotfilder、Christoph le Viseur
DOI:10.1002/ejoc.200400231
日期:2004.9
corresponding 1-unsubstituted tetrahydroisoquinoline alcohol 11 were converted into aldehydes 27 and 33, which cyclized in the presence of different Lewis acids to give the substituted azepino[1,2-b]isoquinolines 34 and 35, respectively, which are key structural features of the alkaloid quinocarcin. The stereoselectivities of the Lewis-acid-catalyzed hetero-ene reaction are highly dependent on the substitution
1,3-二取代的四氢-恶唑并异喹啉酮 19a、b 是通过卡特里茨基的苯并三唑方法从苯丙氨酸中分七步获得的,总产率为 42%。通过使用 LiBH4/MeOH 对酯基进行化学选择性还原,将三环恶唑烷酮 19a 进一步转化为氨基醇 10。化合物 10 和相应的 1-未取代的四氢异喹啉醇 11 被转化为醛 27 和 33,它们在不同的路易斯酸存在下环化,分别得到取代的氮杂[1,2-b] 异喹啉 34 和 35,这是关键生物碱喹诺酮的结构特征。路易斯酸催化的杂烯反应的立体选择性高度依赖于路易斯酸的取代模式和类型。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)