A direct dehydrative coupling protocol for the synthesis of 3-vinylindoles using easily available indoles and simple ketones as substrates was developed with the aid of a sulfonyl-containing Brønsted acid ionic liquid. The salient features of this protocol are high synthetic efficiency, a metal- and solvent-free system, a recyclable catalyst, mild conditions and easy product isolation. With the ionic
借助含磺酰基的布朗斯台德酸离子液体,开发了一种使用容易获得的吲哚和简单的酮为底物合成3-乙烯基吲哚的直接脱水偶联方案。该协议的主要特点是合成效率高,无金属和无溶剂系统,可循环使用的催化剂,条件温和且产品易于分离。使用离子液体催化剂,还以2-羟基甲基吲哚和苯乙酮为起始原料,开发了迄今为止尚未报道的简单的吲哚[3,2- b ]咔唑骨架的构建方法。
Brønsted Acid Ionic Liquid as a Solvent-Conserving Catalyst for Organic Reactions
sulfonyl‐containing ammonium‐based Brønstedacidionic liquid was prepared and used as a liquid heterogeneous catalyst for organic reactions. The unique macroscopic phase heterogeneity of the IL in the reaction system not only ensures an excellent catalytic activity of the IL catalyst but also avoids the use of organic reaction solvents. The catalyst system is applicable for a wide range of reactions.
In the absence of an external reductant, C3-cycloalkylated indole could be synthesized through reductive alkylation of indole with cyclic ketone using a sulfonyl-functionalized Brønsted acid ionic liquid as a catalyst. Water generated in the initial stage of the reaction played a key role in rendering the reductive coupling possible. The reaction proceeds most likely in a radical way.
Facile synthesis of densely substituted chroman derivatives through Brønsted acid ionic liquid catalyzed three-component reactions of aromatic aldehydes, 1,1-diarylethylenes and nucleophiles
densely substituted chroman derivatives were synthesized through hitherto unreported three-componentreactions of aromatic aldehydes, 1,1-diarylethylenes and nucleophiles. The representative reactions involve (i) condensation of benzaldehyde, 2-naphthol and 1,1-diphenylethylene and (ii) selective assembly of salicylaldehyde, indole and 1,1-diphenylethylene. The reactions were performed under solvent-free
media has emerged as a new facet of green chemistry. In this paper, a sulfone‐containing imidazolium‐based Brønsted acid ionic liquid was prepared and used as a recyclable acid catalyst. The ionic liquid catalyst enables the use of an industrially acceptable and environmentally benign solvent, butyl acetate, as the reaction medium. The ionic liquid/butyl acetate biphasic system was successfully utilized