28122-29-4Relevant academic research and scientific papers
An Efficient Synthetic Approach to trans-(NHC)2Pd(R)Br Type Complexes and Their Use in Suzuki–Miyaura Cross-Coupling Reactions
Kumar, Anuj,Prakasham,Gangwar, Manoj Kumar,Vishnoi, Pratap,Butcher, Raymond J.,Ghosh, Prasenjit
, p. 2144 - 2154 (2017)
Mixed organohalidopalladium complexes of the type trans-(NHC)2Pd(R)Br were conveniently obtained from trans-(NHC)2PdBr2 type complexes by a ligand-substitution reaction. In particular, the trans-[1-(1S)-menthyl-4-(R1)-1,2,4-triazol-5-ylidene]2Pd(R2)Br [R1 = Et, R2 = CH2Ph (3a1); R1 = Et, R2 = o-OMeC6H4 (3a2); R1 = R2 = CH2Ph (3b1); R1 = CH2Ph, R2 = o-OMeC6H4 (3b2)] complexes were obtained from the corresponding palladium(II) precursor complexes, 2a,b, by reaction with the respective Grignard reagents, in good to excellent yields (74–93 %). Three of the four mixed organohalidopalladium complexes, 3a1,a2,b1, have been structurally characterized by single-crystal X-ray diffraction, which revealed the trans disposition of the NHC ligands around the palladium center. The use of these mixed organohalidopalladium complexes in the Suzuki–Miyaura cross-coupling reaction was established for all of the complexes, 3a1–b2, which yielded the desired cross-coupled products upon treatment with various ArB(OH)2 [Ar = 1-naphthyl, 4-(1,1′-biphenyl), 9-phenanthrenyl, 4-FC6H4, and 2,6-Me2C6H3] compounds, in the presence of NaOH as a base, in CH3CN, in three hours, under reflux conditions.
N-heterocyclic carbene–palladium complexes for Suzuki–Miyaura coupling reaction with benzyl chloride and aromatic boronic acid leading to diarylmethanes
Chen, Ming-Tsz,Wang, Wan-Rong,Li, Yi-Jun
, (2019/04/08)
A family of N-heterocyclic carbene–palladium(II)–N,N-dimethylbenzylamine complexes ((NHC)LPdCl2; L?=?N,N-dimethylbenzylamine) were synthesized as well as characterized using single-crystal X-ray diffraction and spectroscopic data. These complexes exhibited higher catalytic activities for the Suzuki reaction of benzyl chlorides to afford diarylmethanes under milder conditions than other efficient (NHC)LPdCl2 complexes. Using the optimum conditions, the expected coupling products were obtained in moderate to high yields. All reactions were carried out in air and all starting materials were used as supplied without purification.
Bisulfate Salt-Catalyzed Friedel-Crafts Benzylation of Arenes with Benzylic Alcohols
Tang, Ren-Jin,Milcent, Thierry,Crousse, Benoit
, p. 14001 - 14009 (2018/11/23)
We report here a method of direct Friedel-Crafts benzylation of arenes with benzylic alcohols using cheap and readily available bisulfate salt as the catalyst in hexafluoroisopropanol. The catalytic system is powerful with a quite diverse group of functionalized arenes and benzylic alcohols. These mild conditions provide a straightforward synthesis of a variety of unsymmetrical diarylmethanes in high yield with good to high regioselectivity. An SN1 mechanism involving activation of the hydroxy group through a hydrogen bond is proposed.
MoO3 supported on ordered mesoporous zirconium oxophosphate: An efficient and reusability solid acid catalyst for alkylation and esterification
Miao, Zhichao,Li, Zhenbin,Zhao, Jinping,Si, Weijiang,Zhou, Jin,Zhuo, Shuping
, p. 10 - 21 (2017/12/06)
A series of molybdenum oxide supported on ordered mesoporous zirconium oxophosphate (MoO3/M-ZrPO) materials with different MoO3 loadings (0–20 wt%) and calcination temperatures (500–900 °C) have been designed, synthesized and employed as solid acid catalysts in alkylation and esterification. The XRD, TG-DSC, H2-TPR, N2-physisorption and TEM characterizations were taken to investigate the structural properties and states of introduced MoO3 species. The influence of MoO3 loadings and calcination temperatures in catalytic performance was detailedly investigated and optimal catalytic activity was reached at 10 wt% MoO3 loadings and treated at 700 °C. Moreover, MoO3/M-ZrPO catalysts exhibited outstanding catalytic performance in Friedel-Crafts alkylation of different aromatic compounds and esterification of levulinic acid with 1-butanol. Furthermore, it was noteworthy that the catalyst had superior reusability and no noticeable declines were observed in catalytic performance even after seven runs.
Dinuclear NHC–palladium(II) complexes: synthesis,characterization and application to Suzuki–Miyaura cross-coupling reactions
Wang, Tao,Xu, Kai,Wang, Wanli,Zhang, Anan,Liu, Lantao
, p. 347 - 353 (2018/03/23)
Abstract: Four dinuclear N-heterocyclic carbene–palladium(II) complexes 1–4 were prepared and characterized by elemental analysis and spectroscopic methods. The X-ray crystal structure of complex 2 showed a dinuclear framework in which N-heterocyclic ligands bridge between two square planar palladium(II) units. Each palladium center is surrounded by an imidazolylidene, a nitrogen atom from the central linking ligand, and two trans-chloride ligands. These dinuclear NHC–palladium(II) complexes exhibited efficient catalytic activities for the Suzuki–Miyaura coupling of aryl and benzyl chlorides with arylboronic acids.
Benzylation with Benzyl Alcohol Catalyzed By [ChCl][TfOH]2, a Br?nsted Acidic DES with Reaction Control Self-Separation Performance
Yuan, Bing,Li, Yinglian,Yu, Fengli,Li, Xiaoqiang,Xie, Congxia,Yu, Shitao
, p. 2133 - 2138 (2018/05/29)
Abstract: A deep eutectic solvent with strong Br?nsted acidity was prepared easily by choline chloride and trifluoromethanesulfonic acid. The obtained [ChCl][TfOH]2 catalyst which was characterized by FT-IR, 1H NMR and TG, possessed greatly enhanced stability than trifluoromethanesulfonic acid, and exhibited excellent catalytic performance in benzylation with benzyl alcohol. Especially, the prepared [ChCl][TfOH]2 catalyst could dissolve into the reactants to realize homogeneous catalysis, and then self-separate from the organic phase after reaction due to the entire consumption of benzyl alcohol. As a result, the catalyst could be recovered and reused simply for six-runs without noticeable loss of catalytic performance. Graphical Abstract: [Figure not available: see fulltext.].
Development of Versatile Sulfone Electrophiles for Suzuki-Miyaura Cross-Coupling Reactions
Nambo, Masakazu,Keske, Eric C.,Rygus, Jason P. G.,Yim, Jacky C.-H.,Crudden, Cathleen M.
, p. 1108 - 1112 (2017/08/09)
The development of fluorinated sulfone derivatives as versatile electrophiles for Suzuki-Miyaura cross-coupling reactions is described. Introducing electron-withdrawing groups on the aryl ring of the sulfone facilitates the Pd-catalyzed activation of C-SO2 bonds. Cross-coupling reactions with fluorinated sulfone electrophiles are reported, leading to a variety of multiply arylated products in good yields. The reactivity of this unusual electrophile is benchmarked versus common electrophiles and its use in iterative cross-couplings for concise synthesis of biologically active molecules is described.
Synthesis and characterization of trinuclear N-heterocyclic carbene-palladium(II) complexes and their applications in the Suzuki-Miyaura cross-coupling reaction
Wang, Tao,Liu, Lantao,Xu, Kai,Xie, Huanping,Shen, Hui,Zhao, Wen-Xian
, p. 100690 - 100695 (2016/11/09)
Five novel trinuclear N-heterocyclic carbene-palladium(ii) complexes 5a-e were conveniently synthesized through one-pot reactions of imidazolium salts, tridentate N-heterocycles {tris(4-(pyridin-4-yl)phenyl)amine or tris(4-(pyridin-3-yl)phenyl)amine} and palladium chloride in one step. All of the new complexes have been fully characterized by elemental analysis, 1H, 13C NMR, and IR spectra. Among them, the molecular structures of complex 5d have been determined by X-ray single-crystal diffraction. Moreover, the obtained trinuclear palladium(ii) complexes were the effective catalyst precursors for the Suzuki-Miyaura coupling of aryl as well as benzyl chlorides with arylboronic acids. Under the optimal reaction conditions, the expected biaryl products were obtained in good to almost quantitative yields.
N-heterocyclic carbene-palladium(II)-1-methylimidazole complex-catalyzed Suzuki-Miyaura coupling of benzyl sulfonates with arylboronic acids
Wang, Xiao-Xia,Xu, Bin-Bin,Song, Wen-Ting,Sun, Kai-Xin,Lu, Jian-Mei
, p. 4925 - 4930 (2015/05/05)
The first example of palladium-catalyzed Suzuki-Miyaura coupling between benzyl sulfonates and arylboronic acids was reported in this paper. In the presence of a well-defined, air-stable and easily available NHC-Pd(ii)-Im complex, all reactions worked well to give the desired products in good to almost quantitative yields under the optimal conditions. Electron-rich, -neutral, -poor and sterically-hindered substituents on both substrates are tolerated in such transformation, providing a convenient, efficient and alternative method for the synthesis of diarylmethanes.
A surprising substituent effect provides a superior boronic acid catalyst for mild and metal-free direct Friedel-Crafts alkylations and prenylations of neutral arenes
Ricardo, Carolynne L.,Mo, Xiaobin,McCubbin, J. Adam,Hall, Dennis G.
supporting information, p. 4218 - 4223 (2015/03/14)
The development of more general and efficient catalytic processes for Friedel-Crafts alkylations is an important objective of interest toward the production of pharmaceuticals and commodity chemicals. Herein, 2,3,4,5-tetrafluorophenylboronic acid was identified as a potent air- and moisture-tolerant metal-free catalyst that significantly improves the scope of direct Friedel-Crafts alkylations of a variety of slightly activated and neutral arenes, including polyarenes, with allylic and benzylic alcohols. This method also provides a simple alternative for the direct installation of prenyl units commonly found in naturally occurring arenes. Alkylations with benzylic alcohols occur under exceptionally mild conditions.
