Iridium- and ruthenium-catalysed synthesis of 2,3-disubstituted indoles from anilines and vicinal diols
作者:Matyas Tursky、Linda L. R. Lorentz-Petersen、Lasse B. Olsen、Robert Madsen
DOI:10.1039/c0ob00106f
日期:——
A straightforward and atom-economical method is described for the synthesis of 2,3-disubstituted indoles. Anilines and 1,2-diols are condensed under neat conditions with catalytic amounts of either [Cp*IrCl2]2/MsOH or RuCl3·xH2O/phosphine (phosphine = PPh3 or xantphos). The reaction does not require any stoichiometric additives and only produces water and dihydrogen as byproducts. Anilines containing
描述了一种直接且原子经济的方法来合成2,3-二取代的吲哚。苯胺和1,2-二醇在纯净条件下冷凝,催化量为[Cp * IrCl 2 ] 2/甲醇或RuCl 3 ·xH 2 O /膦 (膦= PPh 3或xantphos)。该反应不需要任何化学计量的添加剂,仅产生水 和 二氢作为副产品。含有甲基,甲氧基,氯和氟取代基的苯胺可以参与环缩合。间位取代的苯胺对6位取代的吲哚具有良好的区域选择性,而不对称的二醇则对6位取代的吲哚具有出色的区域选择性。吲哚在2-位带有芳基或大烷基的异构体。环缩合的机理大概涉及由二醇初始形成α-羟基酮。酮随后与苯胺 生成重新排列为相应的α-羟基亚胺 α-氨基酮。酸或金属催化的亲电闭环,释放出水 然后提供吲哚产品。