Locoselective [4 + 2] Cycloadditions of Vinylindoles with Inverse Electron Demand: A new access of indolyl-substituted and annellated pyridazines
作者:Ulf Pindur、Ludwig Pfeuffer、Myung-Hwa Kim
DOI:10.1002/hlca.19890720109
日期:1989.2.1
2-Vinylindole (1a) and its donor- and acceptor-substituted (E)-derivatives 1b–e react highly locoselectively with dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate (3) to form the novel (indol-2-yl)-1,4-dihydropyridazines 4a and 7 as well as the heterocyclic annellated pyridazines 4b, 5, and 6. The reactions of the structurally related 3-vinylindoles 2a–e with 3 also gave rise to new indol-3-ylpyridazines
2-乙烯基吲哚(1a)及其供体和受体取代的(E)衍生物1b - e与1,2,4,5-四嗪3,6-二羧酸二甲酯(3)发生高度局部选择性反应,从而形成新的(吲哚-2-基)-1,4-二氢哒嗪4a和7以及杂环环化哒嗪4b,5和6。结构上相关的3-vinylindoles的反应2A - ë与3也产生了新的吲哚-3- ylpyridazines 8,9,和10。这些Diels - Alder反应的位置选择性主要受空间效应控制。