From 4,5,6,7-tetrahydroindoles to 3- or 5-(4,5,6,7-tetrahydroindol-2-yl)isoxazoles in two steps: a regioselective switch between 3- and 5-isomers
作者:Lyubov N. Sobenina、Denis N. Tomilin、Maxim D. Gotsko、Igor A. Ushakov、Albina I. Mikhaleva、Boris A. Trofimov
DOI:10.1016/j.tet.2014.05.099
日期:2014.8
(4,5,6,7-Tetrahydroindo1-2-yl]alkynes, synthesized by cross-coupling of 4,5,6,7-tetrahydroindoles with aroyl(hetaroyl)bromoallcynes or ethyl bromopropynoate in the presence of K2CO3, regioselectively cyclize with hydroxylamine to either 3- or 5-(4,5,6,7-tetrahydroindol-2-yl)isoxazoles depending on the acidity of the reaction mixture: in the presence of acetic acid 3-isomers are formed (ca. 100% selectivity), while under neutral conditions the reaction is switched to 5-isomers (94-97% selectivity). (C) 2014 Published by Elsevier Ltd.
由4,5,6,7-四氢吲哚与芳香酰基(杂环芳酰基)溴代炔烃或乙基溴代丙二烯酸酯在K₂CO₃存在下进行交叉偶联反应,可合成出带有4,5,6,7-四氢吲哚-2-基的炔烃。这些炔烃能选择性地与羟胺环化,生成3-或5-(4,5,6,7-四氢吲哚-2-基)异噁唑,这取决于反应混合物的酸性:在醋酸存在下,主要生成3-异构体(约100%选择性),而在中性条件下,则转向生成5-异构体(94-97%选择性)。 ©2014 Elsevier Ltd.出版。