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 was effectively employed, as the key step, in the synthesis of the dibromopyrrolo alkaloid derivative N-Bn-longamide b.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

中文翻译：

---

通过分子内氮杂-迈克尔加成制备多环杂芳族化合物的多功能碱催化途径

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)