Suzuki cross-coupling mediated by tetradentate N-heterocyclic carbene (NHC)–palladium complexes in an environmentally benign solvent

Abstract

A highly effective, easy to handle and environmentally benign process for palladium mediated Suzuki cross-coupling was developed. By utilizing a solid support based NHC-palladium catalyst, cross couplings of aryl bromides with phenylboronic acid were achieved in neat water under air. A high ratio of substrate to catalyst was also realized.

Hydrophilic CNC‐Pincer Palladium Complexes: A Source for Highly Efficient, Recyclable Homogeneous Catalysts in Suzuki–Miyaura Cross‐Coupling

“…The coupling partners were chosen on the basis of their divergent electronic properties that could affect the extent of the reaction. [3,12,13] Nevertheless, the generality of the presented protocol, applicable to electron-rich, neutral and electron-poor bromoarenes and arylboronic acids, was unambiguously proved by the excellent yields obtained in all cases, as displayed in Table 1. The next step in the scheduled evaluation of the properties of catalyst 5 was related to the catalyst loading required to effect the reaction.…”

“…General Remarks 1 H and 13 C NMR spectra were recorded on a Bruker AV-500. Chemical shifts (d) are given in ppm and refer as internal standard to the residual solvent (CDCl 3 : d = 7.26) or TMS: (d = 0.00).…”

“…In this context, the procedure reported by Zhao et al using a silica-supported tetradentate NHC palladacycle [13] and recently employed by ourselves with two NCNtype pincer complexes [4a] was based on the use of neat water and relatively low temperatures (K 2 CO 3 , H 2 O, 100 8C). Therefore, it appeared to be very convenient for our purpose.…”

High‐Turnover Palladium Catalysts in Cross‐Coupling and Heck Chemistry: A Critical Overview

“…[153] Novel mixed Pd catalysts bearing both a heterocyclic carbene and a phosphane as ligands have been used in the Suzuki coupling with aryl chlorides, [154] whereas new carbene-containing palladacycles have found use in the amination of aryl chlorides, [155] in both cases without reaching high TON.…”

Recent Developments in the Applications of Palladium Complexes Bearing N-Heterocyclic Carbene Ligands

“…47,48 Other interesting examples of hydrophilic NHC-based complexes have appeared in the literature. [49][50][51][52][53][54] More recently, Çetinkaya and co-workers have focused their attention to the synthesis of water- …”