An Efficient Base-Free N-Arylation of Imidazoles and Amines with Arylboronic Acids Using Copper-Exchanged Fluorapatite

Abstract

N-Arylation of imidazoles and amines with arylboronic acids was accomplished with copper-exchanged fluorapatite (CuFAP) in methanol at room temperature. The products N-arylimidazoles and N-arylamines were isolated in good to excellent yields. A variety of arylboronic acids were converted to the corresponding N-arylimidazoles and N-arylamines, demonstrating the versatility of the reaction.

An Efficient Recyclable Polymer Supported Copper(II) Catalyst for C–N Bond Formation by N-Arylation

“…Table 6 provides a comparison of the results obtained for our present catalytic system with those reported in the literature. From Table 6, it is seen that the present catalyst exhibited higher yields compared to the other reported system [3,23,27,[45][46][47][48].…”

“…One of the most promising solutions to this problem seems to be the immobilization of the soluble catalysts onto an insoluble matrix using a simplified protocol. However, only limited papers have contributed to N-arylation of alkylamines (not chelating substrates) and various N-H heterocycles in heterogeneous condition [4,23,24]. Homogeneous catalysts have some disadvantages, such as they may easily be destroyed during the course of the reaction and they cannot be easily recovered after the reaction for reuse.…”

An Efficient N‐Arylation of Heterocycles with Aryl‐, Heteroaryl‐, and Vinylboronic Acids Catalyzed by Copper Fluorapatite

“…In a typical experiment, CuFAP (100 mg) [20] was added to a mixture of N-containing heterocycle (1.2 mmol) and arylboronic acid (1 mmol) in MeOH (4 ml) at r.t., and the mixture was stirred for 5 -24 h under an atmosphere of air. The progress of the reaction was monitored by TLC, and on completion of the reaction, the mixture was centrifuged to remove the catalyst, and the centrifugate was concentrated under reduced pressure to give the crude product.…”

“…Recently, we reported the preparation of recyclable heterogeneous Cu-exchanged fluorapatite (CuFAP) and Cu-exchanged (tert-butoxy)apatite catalysts, by incorporating basic species F À /t-BuO À in apatite in situ by co-precipitation and subsequent exchange with Cu II for N-arylation of imidazoles and other heterocycles with chloro-, fluoro-(EW), bromo-, and iodoarenes in good-to-excellent yields for the first time [18] [19]. Later, we reported N-arylation of imidazole, benzimidazole, and amines with arylboronic acids at room temperature under base-free conditions using CuFAP catalyst [20].…”

An efficient polymer-supported copper(II) catalyst for the N-arylation reaction of N(H)-heterocycles with aryl halides as well as arylboronic acids

“…These disadvantages can be overcomed by anchoring the metal on a polymer [21]. There are many examples of heterogeneous catalysts for C-N coupling reactions, and they are prepared by different approaches like encapsulation or immobilization of a catalytically active metal complex on solid supports [22].…”