Synthesis of Anionic Iron(II) Complex Bearing an N-Heterocyclic Carbene Ligand and Its Catalysis for Aryl Grignard Cross-Coupling of Alkyl Halides

Gao, Huanhuan; Yan, Chun-Hui; Tao, Xue-Ping; Xia, Ying; Sun, Hongjian; Shen, Qi; Zhang, Yong

doi:10.1021/om100482w

Cited by 71 publications

(54 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Under the same conditions, a considerably lower activity was seen when 4 or 5 was [12] suggest that a more steric bulkiness provide by the N-substituents should be of benefit to their higher catalytic activity, which can facilitate the reductive elimination to form the desired cross-coupling product together with impose a positive effect to suppress -H elimination [33]. (Table 3, entries 5 and 6) [25]. This is the same pattern as that previously reported with FeCl 3 /phosphine and FeCl 2 / phosphine systems [33].…”

Section: Catalysis Of 1-6mentioning

confidence: 99%

“…As a continuation of our work on the development of iron-based catalysts for carbon-carbon bond formation [24,25], herein we reported the synthesis and structural characterization of a series of iron(III)-containing imidazolium salts (1)(2)(3)(4)(5)(6) and their use in the catalytic cross-coupling of aryl Grignard reagents with alky halides bearing -hydrogens.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Synthesis, structure of iron(III)-containing imidazolium salts and their catalytic activity in the alkylation of aryl Grignard reagents

Xia

Yan

et al. 2012

Chin. Sci. Bull.

Self Cite

View full text Add to dashboard Cite

A series of iron(III)-containing imidazolium salts of the general formula [DRim] [FeX 4 ] (R = 2,6-diisopropylphenyl, IPr, X = Cl, 1; R = IPr, X = Br, 2; R = tertbutyl, t Bu, X = Cl, 3; R = isopropyl, i Pr, X = Cl, 4; R = benzyl, Bn, X = Cl, 5; R = Bn, X = Br, 6) have been prepared in high yields via reactions of anhydrous ferric halides with equivalent of the corresponding N,N-dihydrocarby-limidazolium halides, where 2-6 are novel ones. All of the complexes were characterized by elemental analysis, Raman spectroscopy, electrospray ionization mass spectroscopy, and X-ray crystallography for 1 and 2. All of them were non-hygroscopic and air-stable, with four of them existing as solids (1-4) and two as liquids (5 and 6) at room temperature. A preliminary catalytic study on the coupling of 4-tolylmagnesium bromide with cyclohexyl bromide revealed that 1 and 3 possessed the highest activity. In comparison, 2, 4 and 5 exhibited moderate activity and the least active complex was 6. shown to be capability in this regard. Fe(acac) 3 (acac = acetylacetonate) are also active [10], although the addition of an amine additive was required to achieve a higher yield of the cross-coupled product [11]. Notably, an easily prepared iron(III)-containing imidazolium salt [bmim] [FeCl 4 ] (bmim = 1-butyl-3-methylimidazolium cation) can be used as a recyclable catalyst for the aryl Grignard cross-coupling of alkyl halides [12]. The use of imidazolium chloride can modify the highly hygroscopic FeCl 3 into an non-hygroscopic and air-stable complex, which provides a practical strategy for the design of iron(III)-based catalyst with potential large-scale applications [11].[bmim] [FeCl 4 ] has already been successfully used as a catalyst in other organic transformations, including the Friedel-Crafts sulfonylation of aromatics [13], a Biginelli condensation for the synthesis of dihydropyrimidinones [14], 2,5-norbornadiene dimerization [15], oxidative desulfurization of fuels [16], the glycolysis of poly(ethylene terephthalate) [17], and the regioselective benzylation of arenes and heteroarenes [18].

show abstract

Section: Catalysis Of 1-6mentioning

confidence: 99%

mentioning

confidence: 99%

Synthesis, structure of iron(III)-containing imidazolium salts and their catalytic activity in the alkylation of aryl Grignard reagents

Xia

Yan

et al. 2012

Chin. Sci. Bull.

Self Cite

View full text Add to dashboard Cite

show abstract

“…(1) was selected, as it represents a prototype cross-coupling of aryl Grignard reagents with alkyl halides bearing -hydrogens [20].…”

Section: Catalysis With [Diprim][fecl 4 ]mentioning

confidence: 99%

“…As a continuation of our work on the development of iron-based catalysts for carbon-carbon bond formation [20], here we report the modification of anhydrous …”

mentioning

confidence: 93%

An efficient and recyclable iron(III)-containing imidazolium salt catalyst for cross-coupling of aryl Grignard reagents with alkyl halides

et al. 2012

Self Cite

View full text Add to dashboard Cite

1,3-Bis(2,6-diisopropylphenyl)imidazolium chloride, [DIPrim]Cl, was used to produce a novel iron(III)-containing imidazolium salt [DIPrim] [FeCl 4 ], which included a N,N-diarylimidazolium cation (R = 2,6-diisopropylphenyl), [DIPrim] + , and tetrachloroferrate(III) anion, [FeCl 4 ]  . This compound was an effective and easy-to-use catalyst for the cross-coupling of aryl Grignard reagents with primary and secondary alkyl halides bearing -hydrogens. After simply decanting the cross-coupling product in the ether layer, [DIPrim] [FeCl 4 ] could be reused in at least four successive runs without significant loss of catalytic activity. The transition metal-catalyzed Grignard cross-coupling reaction is a powerful and widely used method for the construction of carbon-carbon bonds [1]. Although a variety of palladium or nickel-based catalysts are particularly effective for the cross-coupling of alkenyl or aryl halides, recent reports on the use of alkyl halides, especially those with -hydrogen atoms, as substrates suggests iron catalysis has potential in this field [2,3]. In comparison with established palladium or nickel-based systems, iron-based catalysts offer a cost efficient, safe and more environmentally benign approach, and the capacity to suppress undesirable -hydride eliminations.To date, a variety of iron-based catalysts have been developed for the cross-coupling of an aryl Grignard reagent with primary or secondary alky halides bearing -hydrogens. For example, well-defined iron complexes, such as the iron (II) tetrakisferrate complex [4], iron(III) salen complexes [5], iron(II) or iron(III) imine complexes [6] and iron(III)amine-bis(phenolate) complexes [7], have shown good crosscoupling activity. In addition, although Fe(acac) 3 (acac = acetylacetonate) can catalyze this cross-coupling reaction [8], amine additives are necessary to achieve higher yields of the cross-coupled product [9]. Notably, FeCl 3 can be used effectively in the presence of appropriate additives, such as amines [9][10][11], phosphines, phosphites, arsines and carbene precursors [12]. Although the direct use of FeCl 3 generally suffers from limitations such as high hygroscopicity of FeCl 3 and the variable yield according to the purity and commercial source of FeCl 3 [13], this method appears particularly attractive because of the simplicity and low cost of the metal salt combined with the high efficiency of the catalytic system. Consequently, this method represents a very powerful approach, if these limitations can be overcome [9,11].Two reports describing the use of FeCl 3 have appeared in the literature. Cahiez et al. [9] discovered that hygroscopic FeCl 3 could be easily modified into a hydrophobic and airstable iron(III) complex [(FeCl 3 ) 2 (tmeda) 3 ] (tmeda = N,N,N′,N′-tetramethylethylenediamine) by direct reaction of FeCl 3 with tmeda in a 2 : 3 molar ratio. Moreover, this complex showed significantly better activity than a stoichiometric mixture of FeCl 3 and tmeda [10,11]. Of particular note is a

show abstract

“…A half-sandwich iron-NHC complex was reported as an efficient catalyst for CH bond activation/borylation of furans and thiophenes [14,15], hydrogen transfer reactions [16], and hydrosilylation of carbonyl derivatives [17]. Several iron complexes, including mononuclear complexes containing monodentate [18][19][20] or polydentate NHC ligands [21][22][23][24][25], iron clusters [26][27][28], and polymeric iron complexes [29], have been recently reported. However, compared to noble metal-NHC complexes [30,31], the organometallic chemistry of iron-NHC complexes has not been well explored.…”

mentioning

confidence: 99%

Reactions of [FeL2(CH3CN)2](PF6)2 (L = N-pyrimid-2-ylimidazol-ylidene) with N-, P-, O-, and S-donors and its catalytic activity

Zhang

Liu

et al. 2012

Chin. Sci. Bull.

View full text Add to dashboard Cite

Reactions of [FeL 2 (CH 3 CN) 2 ] 2+ (L = N-pyrimid-2-ylimidazolylidene) with various N-, P-, O-, and S-donors were investigated. By replacing the labile acetonitrile, various iron-NHC complexes containing additional N-, P-, O-, and S-ligands were prepared. All the iron-NHC complexes were fully characterized by NMR spectroscopy and X-ray crystallography. [30,31], the organometallic chemistry of iron-NHC complexes has not been well explored. We [32] recently reported that iron-NHC complexes can be prepared from iron powder with imidazolium salts or an Ag-NHC complex in air. Alternatively, iron-NHC complexes can be electrochemically prepared using an imidazolium salt as the supporting electrolyte [33]. These synthetic procedures allow for scaling the preparation of iron-NHC complexes, and thus offer more opportunity for careful investigation of the reactivity and application of iron-NHC complexes. In this paper, we report the reactions of [FeL 2 (CH 3 CN) 2 ] 2+ (L=N-pyrimid-2-ylimidazolylidene) with N-, P-, O-, and S-donors and the structural characterization of resulting iron(II)-NHC complexes.

show abstract

Synthesis of Anionic Iron(II) Complex Bearing an N-Heterocyclic Carbene Ligand and Its Catalysis for Aryl Grignard Cross-Coupling of Alkyl Halides

Cited by 71 publications

References 58 publications

Synthesis, structure of iron(III)-containing imidazolium salts and their catalytic activity in the alkylation of aryl Grignard reagents

Synthesis, structure of iron(III)-containing imidazolium salts and their catalytic activity in the alkylation of aryl Grignard reagents

An efficient and recyclable iron(III)-containing imidazolium salt catalyst for cross-coupling of aryl Grignard reagents with alkyl halides

Reactions of [FeL2(CH3CN)2](PF6)2 (L = N-pyrimid-2-ylimidazol-ylidene) with N-, P-, O-, and S-donors and its catalytic activity

Contact Info

Product

Resources

About