作者:Boris A. Trofimov、Ol'ga A. Tarasova、Al'bina I. Mikhaleva、Nina A. Kalinina、Lidiya M. Sinegovskaya、Jochem Henkelmann
DOI:10.1055/s-2000-7618
日期:——
Heterocyclization of ketoximes with propyne or allene in superbase systems MOR/DMSO (M = K, Cs; R = H, t-Bu), which leads to 2-alkyl(aryl, hetaryl)-5-methyl- and 2,3-dialkyl-5-methylpyrroles or 2-methyl-4,5,6,7-tetrahydroindole in yields of up to 63%, has been accomplished for the first time. The reaction is mostly regioselective affording mainly or exclusively 2,5-di- and 2,3,5-trisubstituted pyrroles. The minor isomers in most cases are the corresponding 2,4-di and 2,3,4-trisubstituted pyrroles, only in the case of acetoxime the isomer ratio is ca 1 : 1. For oximes of methyl isopropyl ketone and pinacolone, the 4-methyl-isomers become predominant (78, 83%, respectively).
在 MOR/DMSO(M = K、Cs;R = H、t-Bu)超基体系中,酮肟与丙炔或烯的异环化反应首次完成,该反应可生成 2-烷基(芳基、庚基)-5-甲基和 2,3-二烷基-5-甲基吡咯或 2-甲基-4,5,6,7-四氢吲哚,收率高达 63%。该反应大多具有区域选择性,主要或完全生成 2,5-二和 2,3,5-三取代的吡咯。在大多数情况下,次要异构体是相应的 2,4- 二和 2,3,4- 三取代吡咯,只有在乙酮肟的情况下,异构体比例约为 1:1。在甲基异丙基酮和频哪酮的肟中,4-甲基异构体占主导地位(分别为 78%和 83%)。