Palladium–N-heterocyclic carbene complexes for the Mizoroki–Heck reaction: An appraisal

Abstract

This article presents a review of the most significant developments with N-heterocyclic carbene (NHC)epalladium catalytic systems used for the Heck reaction. For more than the past two decades, a large number of new NHCePd complexes have been synthesized and characterized. These studies focused on NHCs as a phosphine analogue, but the current review highlights the differences with particular ligands so as to attain a suitable balance between the electronic and bulky environments around the metal. NHCs have gained wide recognition as these ligands act as excellent s-donors that form stable metaleNHCs with strong metalecarbon bonds. For this reason, metaleNHCs are commonly used as they are highly reactive and can selectively serve as catalysts for various chemical transformations. The objective of our article is to highlight significant recent progress in NHCePd(II) complexes and provide an overview of their extensive interaction in the MizorokieHeck reaction.

One-Pot Tandem Hiyama Alkynylation/Cyclizations by Palladium(II) Acyclic Diaminocarbene (ADC) Complexes Yielding Biologically Relevant Benzofuran Scaffolds

“…With the success of the transition-metal N-heterocyclic carbene (NHC) complexes in homogeneous catalysis being well-recognized now, 1−15 their application in more challenging domains of catalysis such as bifunctional catalysis, 16,17 asymmetric catalysis, 18 and the tandem reactions 19 are of contemporary interest. Alongside, the quest for exploring new variants of the carbene ligands is being simultaneously pursued for meeting the demands of these intriguing catalyses.…”

“…Alongside, the quest for exploring new variants of the carbene ligands is being simultaneously pursued for meeting the demands of these intriguing catalyses. 1−3,5,6,20 In this context, a special class of heteroatom-stabilized singlet carbene ligands in the form of the acyclic diaminocarbene (ADC) is worth mentioning. 21−31 Owing to their remarkably simple preparative procedures, as opposed to the long and protracted preparation methods of the contemporary phosphine and the NHC ligands, the ADC ligands have attracted attention lately.…”

Imidazolium-Based N-Heterocyclic Carbenes (NHCs) and Metal-Mediated Catalysis

“…The coupling reactions catalyzed by transition metal-NHC complexes involve both C-C bond formation reactions such as Mizoroki-Heck [61,62], Sonogashira [63][64][65], Negishi [66][67][68], Hiyama [69][70][71], Suzuki-Miyaura [72][73][74], Kumada coupling [75,76], C-X (X = B, N, O) bond formation reactions such as Buchwald-Hartwig amination [77][78][79] and Ullmann coupling [80-82] etc. Recently, the coupling reactions catalyzed by the NHC-transition metal complexes have found to be efficient with commercially viable metal salts such as iron, cobalt, and nickel.…”

“…One of the best examples to demonstrate the significance of organometallic complexes is their role as catalysts in olefin metathesis, which is having numerous synthetic applications and commercial significance. There are different types of Few well-known NHC-transition metal-based catalytic applications [13,[61][62][63][64][65][66][67][68][69][70][71][72][73][74].…”

Synthesis of some new distyrylbenzene derivatives using immobilized Pd on an NHC-functionalized MIL-101(Cr) catalyst: photophysical property evaluation, DFT and TD-DFT calculations

“…43,44 In this work, in continuation of our program on the synthesis of stilbene derivatives, [45][46][47][48][49][50] a highly efficient heterogeneous catalyst system [Pd-NHC-MIL-101(Cr)] 51 was introduced to be applied in the synthesis of stilbene derivatives using Mizoroki-Heck coupling reaction. [52][53][54][55][56][57] The Pd-NHC-MIL-101(Cr) catalyst system showed remarkable catalytic activity in the Heck reaction 51 and in order to further show its utility in organic synthesis we investigate its applicability in the synthesis of distyrylbenzenes (DSBs). The synthetic pathway toward synthesis of [Pd-NHC-MIL-101(Cr)] catalyst system is shown in Scheme 1.…”