A catalytic new synthetic approach to 3,4-dihydropyrazino[1,2-a]indol-1(2H)-ones by intramolecular 1,4-addition of readily available α,β-unsaturated esters, is described. Here, the use of a range of organic as well as inorganic bases (5–10 mol-%) allowed a fast (30 min) and regioselective ring-closing reaction to be performed in high yields under simple operational conditions. Moreover, the protocol
描述了一种通过分子内 1,4-加成容易获得的 α,β-不饱和酯来合成 3,4-二氢
吡嗪并 [1,2-a]indol-1(2H)-ones 的一种新的催化合成方法。在这里,使用一系列有机和
无机碱(5-10 mol%)可以在简单的操作条件下以高产率进行快速(30 分钟)和区域选择性的闭环反应。此外,该方案被有效地用作合成二
溴吡咯并
生物碱衍
生物 N-Bn-longamide b 的关键步骤。 (© Wiley-
VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)