Suzuki-Miyaura reaction palladium

The Suzuki-Miyaura reaction, first reported by Suzuki and co-workers in 1979 [87], is the metal-mediated (often palladium) coupling of organic electrophiles such as alkenyl... 

Cazin and co-workers recently reported on the use of the well-defined dimer complexes [Pd( a-C1)(C1)(NHC)]2 that are commercially available, and perform exceedingly well in the Suzuki-Miyaura reaction involving aryl chlorides [108]. The Cazin group has also recently disclosed well-defined mixed NHC/phosphite palladium systems of the type [PdCl2(NHC) P(OR)3j], enabling the Suzuki-Miyaura of aryl chlorides at 0.1 mol% Pd loading [109]. 

Other successful examples of catalysts containing NHC ligands are found in palladium- and nickel-catalyzed carbon-carbon bond formations. The catalyst development with these metals has focused in particular on Heck-type reactions, especially the Mizoroki-Heck reaction itself [Eq. (42)] and various cross coupling reactions [Eq. (43)], e.g., the Suzuki-Miyaura reaction ([M] = and the Kumada-Corriu reaction ([M] = MgBr). " Related reactions like the Sonogashira coupling [Eq. (44)]326-329 Buchwald-... 

Application of the complexes 63 in the Mizoroki-Heck reaction did not reveal higher activity than the previously examined palladium(II) complexes. However, in the Suzuki-Miyaura reaction, a drastically increased activity was observed with complex 63. Catalysis starts without a measurable induction period at mild temperatures accompanied by an extraordinarily high turnover frequency (TOF) of 552 [mol product x mol Pd x h ] at the start of the reaction for the coupling of p-chlorotoluene and phenyl boronic acid [Eq. (48)]. ... 

The Suzuki-Miyaura reactions with relatively inert arylchloride are known to require palladium complexes possessing highly electron-rich ligands which favor the oxidative addition of the arylchloride into Pd(0)-complex (Scheme 11) [67-69]. Herrmann et al. showed that the utilization of NHC ligands with bulky substituents... 

Historically, one of the most important limitations of the Suzuki-Miyaura reaction was the poor reactivity of organic chlorides, attributed to the strength of the C-Cl bond. Aryl chlorides are very attractive halides due to their low cost and wider diversity of available compounds. Prior to 1998, reports of effective palladium-catalyzed Suzuki reactions of aryl chlorides were limited to activated substrates, and generally employing very high temperatures. In that year. 

Along with palladium, several metal-based catalysts have been used for the Suzuki-Miyaura reaction. Zhou and Fu have reported on the use of Ni(COD)2 and bathophenanthroline for the coupling of unactivated secondary bromides... 

Cross-coupling reactions 5-alkenylboron boron compounds, 9, 208 with alkenylpalladium(II) complexes, 8, 280 5-alkylboron boron, 9, 206 in alkyne C-H activations, 10, 157 5-alkynylboron compounds, 9, 212 5-allylboron compounds, 9, 212 allystannanes, 3, 840 for aryl and alkenyl ethers via copper catalysts, 10, 650 via palladium catalysts, 10, 654 5-arylboron boron compounds, 9, 208 with bis(alkoxide)titanium alkyne complexes, 4, 276 carbonyls and imines, 11, 66 in catalytic C-F activation, 1, 737, 1, 748 for C-C bond formation Cadiot-Chodkiewicz reaction, 11, 19 Hiyama reaction, 11, 23 Kumada-Tamao-Corriu reaction, 11, 20 via Migita-Kosugi-Stille reaction, 11, 12 Negishi coupling, 11, 27 overview, 11, 1-37 via Suzuki-Miyaura reaction, 11, 2 terminal alkyne reactions, 11, 15 for C-H activation, 10, 116-117 for C-N bonds via amination, 10, 706 diborons, 9, 167... 

An efficient aqueous phase Suzuki-Miyaura reaction of activated aryl chlorides with aryl boronic acids has been reported. The method uses a new D-glucosamine-based dicyclohexylarylphosphine ligand for the palladium catalyst and works well with nitro-and cyano-activated chlorides.32 The aryl fluoride bond has been considered inert to palladium-catalysed substitution reactions. However, a computational study, backed up by experiment, shows that the presence of a carboxylate group ortho to fluorine will allow reaction both with phenylboronic acids in a Suzuki-type reaction and with organotin reagents in a Stille-type reaction the presence of the adjacent oxyanion stabilizes the transition state.33... 

A recent addition to this field is the polymer-supported di(2-pyridyl)-methylamine-palladium dichloride complex covalently attached to a styrene-alt-maleic acid anhydride copolymer. Turnover numbers as high as 105 were reported and a couple of microwave-heated Suzuki-Miyaura reactions could be performed in neat water [134], 2-Pyridinealdoxime-based Pd(II)-... 

Bromo- and iodoimidazoles are useful intermediates for further functionalization. 4(5)-Aryl- I //-imidazoles 57 can be efficiently and selectively prepared by palladium-catalyzed Suzuki-Miyaura reaction of commercially available 4(5)-bromo-l//-imidazole 56 with arylboronic acids under phase-transfer conditions, which then underwent highly selective palladium-catalyzed and copper(I) iodide mediated direct C-2-arylation with a variety of aryl bromides and iodides under base-free and ligandless conditions to produce 2,4(5)-diaryl-l//-imidazoles 58 in modest to good yields <07JOC8543>. A new procedure for the synthesis of a series of substituted 2-phenylhistamines 60 utilizing a microwave-promoted Suzuki... 

In an ESI-MS monitoring study of the Suzuki-Miyaura reaction using a dichloro-bis(aminophosphine) palladium precatalyst, binuclear Pd complexes were detected after the reaction went to completion, indicating a catalyst sink or a resting state. Addition of starting reagents resumes the reaction, suggesting the active role of the binuclear complex as a reservoir of mononuclear active catalyst. Other interpretations propose the involvement of Pd nanoparticles in which binuclear Pd complexes act as a precursor or perhaps even the active catalyst, but the last possibility seems unlikely. A mechanism for this transformation was proposed based on the intercepted species (Scheme 10) [62]. 

The palladium-catalyzed Suzuki-Miyaura reaction of 3,5-dibromo-2-pyronc 100 with benzo[, ]furan-2-boronic acid 101 was applied to the synthesis of 3-(benzo[ ]furan-2-yl)-5-bromo-pyrone 102 in 50% yield (Equation 92) <2004SL2197>. 

Bulky ligands as above have also proved to be effective in other palladium-catalyzed reactions of aryl halides, e.g., amination [16-19], Suzuki-Miyaura reaction [20-22], Mizoroki-Heck reaction [23, 24], Migita-Kosugi-Stille reaction [25], and aryloxylation and alkoxylation [26-28] as well as the reaction with various carbon nucleophiles as described below. The ligands are considered to enhance both the initial oxidative addition of aryl halides and the reductive elimination of products [29, 30]. The effectiveness of the commercially available simple ligand, P(f-Bu)3, was first described for the amination by Nishiyama et al. [16]. 

Liao et al. used a carboxylic acid amide functionalised carbene and a phosphane in a mixed NHC/phosphane palladium(II) catalyst [261]. The system shows the usual ligand exchange behaviour meaning that the PPhj ligand can be substituted by PCyj. This made it possible to study the influence of the phosphane ligand on the performance of the catalyst. In the Suzuki-Miyaura reaction between phenylboronic acid and p-chloroacetophenone, the yield changes dramatically. When PCyj is chosen as the phosphane ligand, then quantitative yield is observed (for both the saturated and unsaturated NHC), but in the case of PPhj the yield drops to 8% (unsaturated NHC) or even 4% (saturated NHC). When... 

The palladium-catalyzed coupling of boronic acids (as well as other boron derivatives) with aryl and vinyl halides and psendohalides is known as the Suzuki or Suzuki-Miyaura reaction. Because boron is nontoxic, this reaction has been used in pharmaceutical syntheses. In addition, hydroboration or borate substitution allows for the synthesis of virtually any desired coupling partner. For these reasons, as well as the high yields and functional group compatibility, the Suzuki reaction is the first reaction to consider for carrying out a cross coupling. Representative substrates and catalysts are shown in Scheme 17. The various bases are used to generate four-coordinate boron ate complexes that are more reactive in transmetalation. 

A quite obvious solution to this problem is to replace both partners of the crosscoupling reaction with simple arenes by the cleavage of C-H bond during the coupling reaction. To assess this possibility, the catalytic cycle of the Suzuki-Miyaura reaction is depicted in Scheme 2. Palladium-catalyzed Suzuki-Miyaura reaction follows a similar catalytic cycle to those of many other cross-coupling... 

A few interesting papers have appeared with ligandless and solvent-free Suzuki-Miyaura reactions using cheap palladium powder and potassium fluoride on alumina. The catalysts have been recycled and used through several reaction cycles and the products were collected by a simple filtration, adding to the preparative ease of the method [35]. Potassium fluoride on alumina has also been used in the solvent-free synthesis of unsymmetrical ketones, with good results [36, 37]. 

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