- Palladium-catalyzed cross-coupling of benzyltitanium(IV) reagents with aryl fluorides
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The first palladium-catalyzed cross-coupling between benzyltitanium(IV) reagents with aryl fluorides is reported. A variety of diarylmethanes can be prepared in good to excellent yields by the catalyst system of PdCl2(dppf)2 associated with 1-[2-(di-tert-butylphosphanyl)phenyl]-4-methoxypiperidine. This reaction offered a highly efficient approach to diarylmethanes that are commonly found in life-changing drug molecules. Graphical abstract: [Figure not available: see fulltext.]
- Li, Yan
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- METHOD FOR PRODUCING ARENE COMPOUNDS AND ARENE COMPOUNDS PRODUCED BY THE SAME
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Provided is a method for producing (alkyl)arene compounds represented by Formulae 3-1, 3-2, and 3-3 by the Friedel-Crafts alkylation reaction of alkyl halide compounds and arene compounds using organic phosphine compounds as a catalyst.
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Paragraph 0073
(2021/06/26)
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- Alumina grafted SBA-15 sustainable bifunctional catalysts for direct cross-coupling of benzylic alcohols to diarylmethanes
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AlSBA-15 catalysts possessing Br?nsted acid and Lewis acid-base bifunctionalities catalyze the direct arylation of benzyl alcohols to diarylmethanes with an 85% product yield through C-O bond activation. 2 and 4wt%AlSBA-15 catalysts have been synthesised by adopting a simple and efficient post-synthetic metal implantation route. The synthesised catalysts were characterized using XRD, N2 adsorption and desorption, 27Al MAS NMR, XPS, HR-TEM, NH3 and CO2-temperature-programmed desorption (TPD) and pyridine-transmission-FTIR spectroscopy techniques to confirm the existence of Br?nsted acid and Lewis acid-base bifunctionalities. Through various control experiments, it is verified that Br?nsted acid sites activate the benzyl alcohol and Lewis base sites interact with phenylboronic acid concurrently to accomplish the coupling reaction. In the recyclability study, 4wt%AlSBA-15 preserves its activity and stability up to 5 cycles. The 4wt%AlSBA-15 catalyst unlike homogeneous catalysts does not require additives, long reaction time and expensive metals.
- Rajendran, Chandran,Satishkumar, Govindaswamy,Lang, Charlotte,Gaigneaux, Eric M.
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p. 2583 - 2592
(2020/05/14)
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- Ni(NIXANTPHOS)-Catalyzed Mono-Arylation of Toluenes with Aryl Chlorides and Bromides
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A nickel-catalyzed cross-coupling of toluene derivatives with both aryl bromides and chlorides using a NIXANTPHOS-ligated nickel(II) complex has been developed. The key factor to success is proposed to be the catalyst activation of toluene by a cation-π complex, enabling methyl arenes (pKa ≈ 43) to be deprotonated with the relatively mild base NaN(SiMe3)2. This method facilitates access to a variety of sterically and electronically diverse hetero- and nonheteroaryl-containing diarylmethanes.
- Jiang, Hui,Sha, Sheng-Chun,Jeong, Soo A,Manor, Brian C.,Walsh, Patrick J.
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supporting information
p. 1735 - 1739
(2019/03/20)
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- Nickel-Catalyzed C(sp2)?C(sp3) Kumada Cross-Coupling of Aryl Tosylates with Alkyl Grignard Reagents
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Aryl tosylates are an attractive class of electrophiles for cross-coupling reactions due to ease of synthesis, low price, and the employment of C?O electrophiles, however, the reactivity of aryl tosylates is low. Herein, we report the Ni-catalyzed C(sp2)?C(sp3) Kumada cross-coupling of aryl tosylates with primary and secondary alkyl Grignard reagents. The method delivers valuable alkyl arenes by cross-coupling with challenging alkyl organometallics possessing β-hydrogens that are prone to β-hydride elimination and homo-coupling. The reaction is catalyzed by an air- and moisture stable-Ni(II) precatalyst. A broad range of electronically-varied aryl tosylates, including bis-tosylates, underwent this transformation, and many examples are suitable at mild room temperature conditions. The combination of Ar?X cross-coupling with the facile Ar?OH activation/cross-coupling strategy permits for orthogonal cross-coupling with challenging alkyl organometallics. Furthermore, we demonstrate that the method operates with TON reaching 2000, which is one of the highest turnovers observed to date in Ni-catalyzed cross-couplings. (Figure presented.).
- Piontek, Aleksandra,Och?dzan-Siod?ak, Wioletta,Bisz, Elwira,Szostak, Michal
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supporting information
p. 2329 - 2336
(2019/04/13)
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- Deoxygenative cross-electrophile coupling of benzyl chloroformates with aryl iodides
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This work describes Ni-catalyzed cross-electrophile coupling of benzyl chloroformate derivatives with aryl iodides that generates a wide range of diaryl methane products. The mild reaction conditions merit the C-O bond radical fragmentation of benzyl chloroformates via halide abstraction or a single electron reduction by a Ni catalyst. This work offers a new substrate type for cross-electrophile couplings.
- Pan, Yingying,Gong, Yuxin,Song, Yanhong,Tong, Weiqi,Gong, Hegui
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supporting information
p. 4230 - 4233
(2019/05/06)
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- Cross coupling of benzylammonium salts with boronic acids using a well-defined N-heterocyclic carbene-palladium(ii) precatalyst
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N-heterocyclic carbene-palladium(ii)-catalyzed cross-coupling of benzylammonium salts with arylboronic acids for the synthesis of diarylmethane derivatives via C-N bond activation has been developed. Notably, in the presence of the easily prepared and bench-stable Pd-PEPPSI precatalyst, the Csp3-N bond activation of the benzylammonium salt even proceeded smoothly in isopropanol at room temperature.
- Wang, Tao,Guo, Jiarui,Wang, Xiaojuan,Guo, Han,Jia, Dingli,Wang, Hengjin,Liu, Lantao
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p. 5738 - 5741
(2019/03/02)
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- Construction of Di(hetero)arylmethanes Through Pd-Catalyzed Direct Dehydroxylative Cross-Coupling of Benzylic Alcohols and Aryl Boronic Acids Mediated by Sulfuryl Fluoride (SO2F2)
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A practical Pd-catalyzed direct dehydroxylative coupling of (hetero)benzylic alcohols with (hetero)arylboronic acids for the constructions of di(hetero)arylmethane derivatives under SO2F2 was described. This new method provided a strategically distinct approach to di(hetero)arylmethane derivatives from readily available and abundant benzylic alcohols under mild condition.
- Zhao, Chuang,Zha, Gao-Feng,Fang, Wan-Yin,Rakesh,Qin, Hua-Li
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p. 1801 - 1807
(2019/02/07)
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- Cation-π Interactions in the Benzylic Arylation of Toluenes with Bimetallic Catalysts
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A method to directly arylate toluene derivatives with aryl bromides to generate diarylmethanes, which are important building blocks in drug discovery, is described. In this method, KN(SiMe3)2 in combination with a (NIXANTPHOS)Pd catalyst accomplished the deprotonative activation of toluene derivatives to permit cross-coupling with aryl bromides. Good to excellent yields are obtained with a range of electron-rich to neutral aryl bromides. Both electron-rich and electron-poor toluene derivatives are well tolerated, and even 2-chlorotoluene performs well, providing a platform for introduction of additional functionalization. This discovery hinges on the use of a main group metal to activate toluene for deprotonation by means of a cation-π interaction, which is secured by a bimetallic K(NIXANTPHOS)Pd assembly. Mechanistic and computational studies support acidification of toluene derivatives by the K+-cation- π interaction, which may prove pertinent in the development of other, new reaction systems.
- Sha, Sheng-Chun,Tcyrulnikov, Sergei,Li, Minyan,Hu, Bowen,Fu, Yue,Kozlowski, Marisa C.,Walsh, Patrick J.
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supporting information
p. 12415 - 12423
(2018/10/02)
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- Gold(I)-catalyzed Benzylation of (Hetero)aryl Boronic Acids with (Hetero)benzyl Bromides by the Strategy of a SN2-type Reaction
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Herein, the first example of gold-catalyzed benzylation of (hetero)aryl boronic acids with (hetero)benzyl bromides to give the corresponding cross-coupling products in moderate to good yields is reported. The reaction proceeds through a possible intermolecular SN2-type reaction pathway to give a wide variety of di(hetero)arylmethanes as the desired products. An intriguing reaction mechanism has been proposed on the basis of control experiments, 31P-NMR spectroscopic detection and DFT calculations.
- Zang, Wenqing,Wei, Yin,Shi, Min
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supporting information
p. 2791 - 2795
(2018/09/20)
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- Cross-Coupling of Phenol Derivatives with Umpolung Aldehydes Catalyzed by Nickel
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A nickel-catalyzed cross-coupling to construct the C(sp2)-C(sp3) bond was developed from two sustainable biomass-based feedstocks: phenol derivatives with umpolung aldehydes. This strategy features the in situ generation of moisture/air-stable hydrazones from naturally abundant aldehydes, which act as alkyl nucleophiles under catalysis to couple with readily available phenol derivatives. The avoidance of using both halides as the electrophiles and organometallic or organoboron reagents (also derived from halides) as the nucleophiles makes this method more sustainable. Water tolerance, great functional group (ketone, ester, free amine, amide, etc.) compatibility, and late-stage elaboration of complex biological molecules exemplified its practicability and unique chemoselectivity over organometallic reagents.
- Lv, Leiyang,Zhu, Dianhu,Tang, Jianting,Qiu, Zihang,Li, Chen-Chen,Gao, Jian,Li, Chao-Jun
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p. 4622 - 4627
(2018/05/22)
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- Nickel-catalyzed cross-coupling of aldehydes with aryl halides: Via hydrazone intermediates
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Traditional cross-couplings require stoichiometric organometallic reagents. A novel nickel-catalyzed cross-coupling reaction between aldehydes and aryl halides via hydrazone intermediates has been developed, merging the Wolff-Kishner reduction and the classical cross-coupling reactions. Aromatic aldehydes, aryl iodides and aryl bromides are especially effective in this new cross-coupling chemistry.
- Tang, Jianting,Lv, Leiyang,Dai, Xi-Jie,Li, Chen-Chen,Li, Lu,Li, Chao-Jun
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supporting information
p. 1750 - 1753
(2018/02/21)
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- Dinuclear NHC–palladium(II) complexes: synthesis,characterization and application to Suzuki–Miyaura cross-coupling reactions
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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.
- Wang, Tao,Xu, Kai,Wang, Wanli,Zhang, Anan,Liu, Lantao
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p. 347 - 353
(2018/03/23)
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- Bisulfate Salt-Catalyzed Friedel-Crafts Benzylation of Arenes with Benzylic Alcohols
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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.
- Tang, Ren-Jin,Milcent, Thierry,Crousse, Benoit
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p. 14001 - 14009
(2018/11/23)
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- A Zwitterionic Palladium(II) Complex as a Precatalyst for Neat-Water-Mediated Cross-Coupling Reactions of Heteroaryl, Benzyl, and Aryl Acid Chlorides with Organoboron Reagents
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The Suzuki–Miyaura cross-coupling (SMC) reactions of several heteroaryl chlorides, benzyl chlorides, and aryl acid chlorides with (hetero)arylboron reagents have been investigated in the presence of [Pd(HL1)(PPh3)Cl2] (I) [HL1 = 3-[(2,6-diisopropylphenyl)-1-imidazolio]-2-quinoxalinide] as catalyst and K2CO3 as base in neat water. The synthesis of the heterocycle-containing biaryls required the addition of 2 mol-% of a phosphine ligand (PPh3 or X-Phos). A combination of more than 115 substrates were screened and it was found that I is a versatile catalyst that can produce heterocycle-containing biaryls, diarylmethanes, and benzophenones in moderate-to-excellent yields.
- Ramakrishna, Visannagari,Rani, Morla Jhansi,Reddy, Nareddula Dastagiri
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p. 7238 - 7255
(2018/01/01)
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- One-pot borylation/Suzuki-Miyaura sp2-sp3 cross-coupling
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We describe the first one-pot borylation/Suzuki-Miyaura sp2-sp3 cross-coupling between readily available aryl (pseudo)halides and activated alkyl chlorides. This method streamlines the synthesis of diaryl methanes, α-aryl carbonyls and allyl aryl compounds, substructures that are commonly found in life changing drug molecules.
- Whitaker, Luke,Harb, Hassan Y.,Pulis, Alexander P.
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p. 9364 - 9367
(2017/08/23)
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- An Efficient Synthetic Approach to trans-(NHC)2Pd(R)Br Type Complexes and Their Use in Suzuki–Miyaura Cross-Coupling Reactions
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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.
- Kumar, Anuj,Prakasham,Gangwar, Manoj Kumar,Vishnoi, Pratap,Butcher, Raymond J.,Ghosh, Prasenjit
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p. 2144 - 2154
(2017/04/21)
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- Synthesis of Di- and Triarylmethanes through Palladium-Catalyzed Reductive Coupling of N -Tosylhydrazones and Aryl Bromides
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A palladium-catalyzed reductive coupling between N-tosylhydrazones and aryl bromides has been developed. The reaction provides an efficient method for the synthesis of diarylmethanes and triarylmethanes via the formation of C(sp2)-C(sp3) single bonds. This new methodology for the synthesis of diarylmethanes and triarylmethanes is featured by the ready availability of the starting materials, mild reaction conditions, and the tolerance of wide range of functional groups. The reaction follows a pathway including palladium carbene formation, migratory insertion, and reduction of the alkylpalladium(II) intermediate.
- Xia, Yamu,Hu, Fangdong,Xia, Ying,Liu, Zhenxing,Ye, Fei,Zhang, Yan,Wang, Jianbo
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p. 1073 - 1086
(2017/02/24)
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- Efficient N-heterocyclic carbene nickel pincer complexes catalyzed cross coupling of benzylic ammonium salts with boronic acids
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Pyridine-bridged bis-benzimidazolylidene nickel complexes exhibited very high catalytic activity toward cross coupling of inactive (hetero)aryl benzylic ammonium salts with (hetero)aryl and alkenyl boronic acids under mild reaction conditions. Even at 2 mol% catalyst loading, a wide range of substrates for both coupling partners with different steric and electronic properties were well tolerated.
- Liu, Xi-Yu,Zhu, Hai-Bo,Shen, Ya-Jing,Jiang, Jian,Tu, Tao
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p. 350 - 353
(2017/01/28)
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- One-pot reductive coupling reactions of acetyl naphthalene derivatives, tosylhydrazide, with arylboronic acids
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In this study, a one-pot two-step reductive coupling between acetyl naphthalene derivatives, tosylhydrazide, and arylboronic acids, affording substituted 1(or 2)-(1-phenylethyl)naphthalenes in moderate-to-excellent yields, was reported. Notably, solvent played a crucial role in the coupling of 1-acetyl naphthalene derivatives (toluene) or 2-acetyl naphthalene derivatives (1,4-dioxane) as starting materials. Meanwhile, the scope of this one-pot coupling reaction was extended to 1(or 2)-naphthaldehyde substrates. Particularly, the system was also suitable to synthesize 1(or 2)-(1-phenylethyl)naphthalenes on a multi-gram scale, and was applied in the synthesis of naphthylmethyl substituted carbazolyl compounds.
- Shen, Xu,Liu, Ping,Liu, Yang,Liu, Yan,Dai, Bin
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supporting information
p. 785 - 793
(2017/01/16)
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- Synthetic method of diarylmethanes
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The invention discloses a synthetic method of diarylmethanes. The method is characterized in that benzyl pseudohalide and aromatic boric acid are reacted in an organic solvent under alkaline condition. The method employs easily available raw materials, conversion is realized under effect of no transition metal catalysis, water-free and oxygen-free are not required, Lewis acid catalysis is not required, the method has wide substrate universality, and various substituted diarylmethanes can be synthesized by the method.
- -
-
Paragraph 0173; 0174; 0175; 0176; 0177
(2017/08/28)
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- Catalytic Tandem and One-Pot Dehydrogenation-Alkylation and -Insertion Reactions of Saturated Hydrocarbons with Alcohols and Alkenes
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The ruthenium-hydride catalyst has been successfully used for the tandem sp3 C-H dehydrogenation-alkylation reaction of saturated hydrocarbon substrates with alcohols to form the alkyl-substituted alkene and arene products. The analogous one-pot dehydrogenation-insertion of saturated ketones with alkenes and dienes directly yielded synthetically useful 2-alkylphenol and benzopyran products in a highly regio- and stereoselective manner without forming any wasteful byproducts. (Chemical Equation Presented).
- Kim, Junghwa,Pannilawithana, Nuwan,Yi, Chae S.
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p. 8395 - 8398
(2016/12/16)
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- Coupling of arylboronic acids with benzyl halides or mesylates without adding transition metal catalysts
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We report herein a transition-metal-free coupling reaction of arylboronic acids with benzyl halides and mesylates for the construction of C(sp2)[sbnd]C(sp3) bonds. A unique feature of this coupling reaction is the formation regioisomers in some cases. Mechanistic studies suggest that this reaction may proceed via an unprecedented Friedel–Crafts-type reaction pathway under base conditions with the assistance of boronic acid moiety.
- Wu, Guojiao,Xu, Shuai,Deng, Yifan,Wu, Chaoqiang,Zhao, Xia,Ji, Wenzhi,Zhang, Yan,Wang, Jianbo
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p. 8022 - 8030
(2016/11/19)
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- Nickel-Catalyzed Reductive Cross-Coupling of Benzyl Chlorides with Aryl Chlorides/Fluorides: A One-Pot Synthesis of Diarylmethanes
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The first nickel-catalyzed, magnesium-mediated reductive cross-coupling between benzyl chlorides and aryl chlorides or fluorides is reported. A variety of diarylmethanes can be prepared in good to excellent yields in a one-pot manner using easy-to-access mixed PPh3/NHC Ni(II) complexes of Ni(PPh3)(NHC)Br2 (NHC = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene, IPr, 1a; 1,3-di-tert-butylimidazol-2-ylidene, ItBu, 1b) as catalyst precursors. Activation of polychloroarenes or chemoselective cross-coupling based on the difference in catalytic activity between 1a and 1b is used to construct oligo-diarylmethane motifs.
- Zhang, Jie,Lu, Gusheng,Xu, Jin,Sun, Hongmei,Shen, Qi
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supporting information
p. 2860 - 2863
(2016/07/06)
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- An approach to heterodiarylmethanes via sp2-sp3 Suzuki-Miyaura cross-coupling
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The synthesis of a range of structurally diverse diarylmethanes via the Suzuki-Miyaura cross-coupling of aryl methane acetates and arylboronic acids is reported, including several challenging examples containing nitrogen, oxygen and sulfur heteroatoms in one or both coupling partners. A single set of optimized conditions was used to generate the diarylmethanes in 52-91% yield.
- Stewart, Gavin W.,Maligres, Peter E.,Baxter, Carl A.,Junker, Ellyn M.,Krska, Shane W.,Scott, Jeremy P.
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supporting information
p. 3701 - 3706
(2016/06/06)
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- Use of Trifluoromethyl Groups for Catalytic Benzylation and Alkylation with Subsequent Hydrodefluorination
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The electrophilic organofluorophosphonium catalyst [(C6F5)3PF][B(C6F5)4] is shown to effect benzylation or alkylation by aryl and alkyl CF3 groups with subsequent hydrodefluorination, thus resulting in a net transformation of CF3 into CH2-aryl fragments. In the case of alkyl CF3 groups, Friedel-Crafts alkylation by the difluorocarbocation proceeded without cation rearrangement, in contrast to the corresponding reactions of alkyl monofluorides.
- Zhu, Jiangtao,Prez, Manuel,Caputo, Christopher B.,Stephan, Douglas W.
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supporting information
p. 1417 - 1421
(2016/02/14)
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- N-heterocyclic carbene-palladium(II) complexes with benzoxazole or benzothiazole ligands: Synthesis, characterization, and application to Suzuki-Miyaura cross-coupling reaction
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A series of novel N-heterocyclic carbene-palladium(II) complexes 3 were conveniently prepared from commercially available imidazolium salts, palladium chloride, and benzoxazole or benzothiazole in one step. All of the new complexes have been fully characterized by elemental analysis, 1H, 13C NMR, and IR spectra. In addition, the molecular structures of complexes 3a-d have also been determined by X-ray single-crystal diffraction. The obtained palladium(II) catalysts showed efficient catalytic activity toward 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 moderate to high yields.
- Wang, Tao,Xie, Huanping,Liu, Lantao,Zhao, Wen-Xian
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- Synthesis and characterization of trinuclear N-heterocyclic carbene-palladium(II) complexes and their applications in the Suzuki-Miyaura cross-coupling reaction
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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.
- Wang, Tao,Liu, Lantao,Xu, Kai,Xie, Huanping,Shen, Hui,Zhao, Wen-Xian
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p. 100690 - 100695
(2016/11/09)
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- N-Heterocyclic carbene-palladium(II)-1-methylimidazole complex-catalyzed Suzuki-Miyaura coupling of benzyl carbamates with arylboronic acids
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The Suzuki-Miyaura coupling of benzyl carbamates with arylboronic acids was achieved in an environmentally benign medium. Using water as the sole solvent, such transformation took place very well to give the desired diarylmethane derivatives in good to almost quantitative yields in the presence of a well-defined NHC-Pd(ii)-Im complex under mild conditions. It is worth noting here that this is the first example of benzyl carbamates used in coupling reaction, thus affording a new method for the formation of diarylmethanes by palladium-catalyzed C-O bond activation.
- Wang, Xiao-Xia,Luo, Mao-Jun,Lu, Jian-Mei
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p. 11438 - 11444
(2015/12/04)
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- N-heterocyclic carbene-palladium(II)-1-methylimidazole complex-catalyzed Suzuki-Miyaura coupling of benzyl sulfonates with arylboronic acids
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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.
- Wang, Xiao-Xia,Xu, Bin-Bin,Song, Wen-Ting,Sun, Kai-Xin,Lu, Jian-Mei
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p. 4925 - 4930
(2015/05/05)
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- Direct cross-coupling of benzyl alcohols to construct diarylmethanes via palladium catalysis
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A direct arylation to furnish diarylmethanes from benzyl alcohols was realized through Pd(PPh3)4-catalyzed Suzuki-Miyaura coupling via benzylic C-O activation in the absence of any additives. The arylation is compatible with various functional groups. This development provides an atom- and step-economic way to approach a diarylmethane scaffold under mild and environmentally benign conditions. This journal is
- Cao, Zhi-Chao,Yu, Da-Gang,Zhu, Ru-Yi,Wei, Jiang-Bo,Shi, Zhang-Jie
-
supporting information
p. 2683 - 2686
(2015/03/05)
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- Synthesis of diarylmethanes through palladium-catalyzed coupling of benzylic phosphates with arylsilanes
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An efficient approach to the benzylation of arenes has been developed. The reactions described provide straightforward access to diarylmethanes through Pd-catalyzed coupling of benzylic phosphates with arylsilanes in good to excellent yields. The reaction tolerates a wide range of functionalities such as halide, alkoxyl, and nitro groups.
- Zhang, Pengbo,Xu, Jian,Gao, Yuzhen,Li, Xueqin,Tang, Guo,Zhao, Yufen
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p. 2928 - 2932
(2015/01/16)
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- Benzylation of arenes with benzyl ethers promoted by the in situ prepared superacid BF3-H2O
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An efficient and environmentally friendly benzylation of arenes with benzyl ethers as benzyl donors using BF3-Et2O to generate in situ the superacid BF3-H2O as an efficient promotor has been described. A wide variety of functional groups have been investigated and found to be compatible to give the desired diarylmethanes in yields of up to 99%. The crucial role of the moisture content in this transformation has been demonstrated by detailed investigations. This journal is the Partner Organisations 2014.
- Li, Yu,Xiong, Yan,Li, Xueming,Ling, Xuege,Huang, Ruofeng,Zhang, Xiaohui,Yang, Jianchun
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supporting information
p. 2976 - 2981
(2014/06/10)
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- Synthesis, structure, and catalytic applications for ortho - And meta -carboranyl based NBN pincer-Pd complexes
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o- and m-Carborane-based NBN pincer palladium complexes (oCB-L1)Pd, (oCB-L2)Pd, and (mCB-L1)Pd are synthesized in two steps from commercially available starting materials. The pincer complexes were prepared by the reaction of bis-[R(hydroxy)methyl]-1,2-dicarba-closo-dodecaborane (R = 2-pyridyl oCB-L1, 6-methyl-2-pyridyl oCB-L2) or bis-[2-pyridyl (hydroxy)methyl]-1,2-dicarba-meta- dodecaborane (mCB-L1) with [PdCl2(MeCN)2] under mild conditions. The X-ray structure determination of all carboranyl pincer complexes shows unambiguously B-H activation of the carborane cages. The results agree with the Pd-B bonds in all complexes exhibiting strong σ-electron donation. Theoretical calculations reveal the importance of considering the solid state intermolecular hydrogen bonding when investigating the trans influence in organometallic chemistry. A localized orbitals approach has also been applied to analyze the metal oxidation state in the carboranyl pincer complexes. Catalytic applications of (oCB-L1)Pd and (mCB-L1)Pd have shown the complexes are good catalyst precursors in Suzuki coupling in water and with very low amounts of catalyst loadings.
- Tsang, Min Ying,Vinas, Clara,Teixidor, Francesc,Planas, Jose Giner,Conde, Nerea,Sanmartin, Raul,Herrero, Maria Teresa,Dominguez, Esther,Lledos, Agusti,Vidossich, Pietro,Choquesillo-Lazarte, Duane
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p. 9284 - 9295
(2014/11/07)
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- A Palladium Bipyridyl Complex Grafted onto Nanosized MCM-41 as a Heterogeneous Catalyst for Negishi Coupling
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The Negishi coupling of aryl bromides or acyl chlorides with organozinc chlorides catalyzed by a palladium bipyridyl complex anchored on nanosized mobile crystalline material 41 (MCM-41) were investigated. The reactions proceeded smoothly with a very low catalyst loading in THF at 70°C for electron-deficient aryl bromides, which gave good to high yields of the Negishi coupling products. However, reactions in toluene at 110°C were required if electron-rich aryl bromides were employed. For acyl chlorides, the reactions could be performed in THF at 50°C and the corresponding ketones and ynones were obtained in high yields. After centrifugation, it was possible to easily recover the supported catalyst from the reaction mixture, and this could be reused several times without any retreatment or regeneration with only a slight decrease in activity.
- Wu, Wei-Yi,Lin, Tze-Chiao,Takahashi, Tamotsu,Tsai, Fu-Yu,Mou, Chung-Yuan
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p. 1011 - 1019
(2013/05/09)
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- Palladium nanoparticles in glycerol: A versatile catalytic system for C-X bond formation and hydrogenation processes
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Palladium nanoparticles stabilised by tris(3-sulfophenyl)phosphine trisodium salt in neat glycerol have been synthesised and fully characterised, starting from both Pd(II) and Pd(0) species. The versatility of this innovative catalytic colloidal solution has been proved by its efficient application in C-X bond formation processes (X=C, N, P, S) and C-C multiple bond hydrogenation reactions. The catalytic glycerol phase could be recycled more than ten times, preserving its activity and selectivity. The scope of each of these processes has demonstrated the power of the as-prepared catalyst, isolating the corresponding expected products in yields higher than 90%. The dual catalytic behaviour of this glycerol phase, associated to the metallic nanocatalysts used in wet medium (molecular- and surface-like behaviour), has allowed attractive applications in one-pot multi-step transformations catalysed by palladium, such as C-C coupling followed by hydrogenation, without isolation of intermediates using only one catalytic precursor. Copyright
- Chahdoura, Faouzi,Pradel, Christian,Gomez, Montserrat
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supporting information
p. 3648 - 3660
(2014/01/06)
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- Microwave-promoted palladium catalysed Suzuki cross-coupling reactions of benzyl halides with arylboronic acid
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Simple catalytic systems for the coupling of benzyl halides with phenylboronic acid under microwave conditions were tested. Microwave-promoted Suzuki reaction of arylboronic acid with benzyl halides catalysed by PdCl2(PPh3)2 in the mixed solvents DMF/H2O is reported to give diaryl methane derivatives in good to high yield.
- Zhang, Yu-Quan
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p. 375 - 376
(2013/07/26)
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- Direct arylation/alkylation/magnesiation of benzyl alcohols in the presence of grignard reagents via Ni-, Fe-, or Co-catalyzed sp3 C-O Bond activation
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Direct application of benzyl alcohols (or their magnesium salts) as electrophiles in various reactions with Grignard reagents has been developed via transition metal-catalyzed sp3 C-O bond activation. Ni complex was found to be an efficient catalyst for the first direct cross coupling of benzyl alcohols with aryl/alkyl Grignard reagents, while Fe, Co, or Ni catalysts could promote the unprecedented conversion of benzyl alcohols to benzyl Grignard reagents in the presence of nhexylMgCl. These methods offer straightforward pathways to transform benzyl alcohols into a variety of functionalities.
- Yu, Da-Gang,Wang, Xin,Zhu, Ru-Yi,Luo, Shuang,Zhang, Xiao-Bo,Wang, Bi-Qin,Wang, Lei,Shi, Zhang-Jie
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p. 14638 - 14641
(2012/11/07)
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- Fluorous oxime palladacycle: A precatalyst for carbon-carbon coupling reactions in aqueous and organic medium
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To facilitate precatalyst recovery and reuse, we have developed a fluorous, oxime-based palladacycle 1 and demonstrated that it is a very efficient and versatile precatalyst for a wide range of carbon-carbon bond formation reactions (Suzuki-Miyaura, Sonogashira, Stille, Heck, Glaser-type, and Kumada) in either aqueous or organic medium under microwave irradiation. Palladacycle 1 could be recovered through F-SPE in various coupling reactions with recovery ranging from 84 to 95% for the first cycle. Inductively coupled plasma optical emission spectrometry (ICP-OES) analyses of the Pd content in the crude product from each class of transformation indicated extremely low levels of leaching and the palladacycle could be reused four to five times without significant loss of activity.
- Susanto, Woen,Chu, Chi-Yuan,Ang, Wei Jie,Chou, Tzyy-Chao,Lo, Lee-Chiang,Lam, Yulin
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experimental part
p. 2729 - 2742
(2012/05/21)
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- Magnetic core-shell-structured nanoporous organosilica microspheres for the Suzuki-Miyaura coupling of aryl chlorides: Improved catalytic activity and facile catalyst recovery
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New magnetic core-shell-structured nanoporous organosilica microspheres consisting of a Fe3O4 core and an organosilica shell with a built-in N-heterocyclic carbene (NHC) moiety were synthesized through surfactant-directed self-assembly on surface. The structure and composition of the material thus-designed were confirmed by N2 sorption, XRD, TEM, FT-IR, etc. Such composite microspheres possess highly open mesopores (1.6 nm) in the shell, moderate surface area, tunable shell thickness, uniform morphology, high magnetization as well as good coordination ability toward Pd. The catalytic activity test with the Suzuki-Miyaura couplings of challenging aryl chlorides reveals that this Pd-coordinated material is highly active for a wide range of substrates, suggesting highly promising application potentials of the magnetic core-shell-structured nanoporous organosilica. In particular, the catalyst derived from this material is superior to NHC-functionalized MCM-41 microspheres and a commercial Pd/C catalyst in terms of activity and recovery. The catalytic activity enhancement effects may be attributable to the purposely designed core-shell structure with significantly decreased diffusion depth, which is crucial for designing high-performance solid catalysts. The Royal Society of Chemistry 2012.
- Yang, Hengquan,Li, Guang,Ma, Zhancheng
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experimental part
p. 6639 - 6648
(2012/07/28)
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- Tin exchanged heteropoly tungstate: An efficient catalyst for benzylation of arenes with benzyl alcohol
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The partial exchange of tin with the protons of 12-tungstophosphoric acid (TPA) results in a highly active heterogeneous catalyst for benzylation of arenes with benzyl alcohol as benzylating agent. The catalysts were characterized by X-ray diffraction, Laser-Raman and FT-IR of pyridine adsorption. The catalytic activity depends significantly on the extent of tin exchanged with the protons of heteropoly tungstate. The characterization results suggest the presence of Lewis acidic sites by the exchange of tin. The catalyst with partial exchange of Sn showed high benzylation activity, which in turn related to variation in acidity of the catalysts. The catalyst is highly active for benzylation reaction irrespective of the nature of substituted arenes and benzyl alcohols. These catalysts are highly active compared to other acid catalysts used for benzylation of different arenes. The catalyst is easy to separate from reaction mixture and exhibit consistent activity upon reuse. The plausible reaction mechanism based on the role of both Lewis and Bronsted acid sites of the catalyst was discussed.
- Ramesh Kumar, Ch.,Rao, K.T. Venkateswara,Sai Prasad,Lingaiah
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experimental part
p. 17 - 24
(2011/04/21)
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- Palladium nanoparticle catalyzed hiyama coupling reaction of benzyl halides
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An efficient Hiyama coupling reaction between benzylic halide and aryltrialkoxysilane using Pd nanoparticles has been developed. This procedure accommodates various functional groups to yield a diverse range of diarylmethanes which are ubiquitous units of natural products and pharmaceuticals.
- Srimani, Dipankar,Bej, Ansuman,Sarkar, Amitabha
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supporting information; experimental part
p. 4296 - 4299
(2010/09/04)
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- Regioselective arene functionalization: Simple substitution of carboxylate by alkyl groups
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Arenes with various alkyl side-chains were synthesized in high yields and excellent regioselectivities. Starting from toluic and naphthoic acids, the carboxylate group was conveniently substituted by alkyl halides by Birch reduction and subsequent decarbonylation. The method is characterized by inexpensive starting materials and reagents, and methylation of arenes was realized. Besides simple alkyl substituents, the scope of arene functionalization was extended by benzyl, fluoro, amino, and ester groups. We were able to control the alkylation of 1-naphthoic acid during Birch reduction by the addition of tert-butanol. This allowed the regioselective synthesis of mono and bis-substituted naphthalenes from the same starting material.
- Krueger, Tobias,Vorndran, Katja,Linker, Torsten
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experimental part
p. 12082 - 12091
(2010/05/17)
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- Synthesis of novel silyl enol ethers from chlorodimethyl(naphthylphenylmethyl)silanes having a chiral centre and a ketone and their chirality transfer effects in crossed-aldol reactions
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X-ray crystallography was used to determine the stereo structure of a novel chiral organosilicon compound, (2R)-(-)-(1-cyclohexenyloxy)dimethyl(1- naphthylphenylmethyl) silane, which has a chiral centre next to the silicon atom. The crossed-aldol reaction
- Miyakawa, Kenichi,Konakahara, Takeo,Sakai, Norio,Kozawa, Kozo,Gunji, Takahiro,Nagao, Yukinori
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experimental part
p. 46 - 51
(2009/11/30)
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- Palladium-catalyzed synthesis of diarylmethanes: Exploitation of carbanionic leaving groups
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A novel route to the synthesis of diarylmethanes via a Pd-catalyzed α-arylation of benzyl ketones is rseported. By harnessing the inherent reactivity of enolates, it is possible to circumvent the need for a transmetalating reagent such as boron for the co
- Schmink, Jason R.,Leadbeater, Nicholas E.
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supporting information; experimental part
p. 2575 - 2578
(2009/10/02)
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- A metal-free catalytic system for the oxidation of benzylic methylenes and primary amines under solvent-free conditions
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Iodine-pyridine-tert-butylhydroperoxide is developed as a green and efficient catalytic system for the oxidation of benzylic methylenes to ketones and primary amines to nitriles. The reaction conditions are quite mild and environmentally benign, no transition metals, organic solvents or hazard reagents being needed. The oxidation of benzylic methylenes gave the corresponding ketones in excellent yields with complete chemoselectivity, while the oxidation of primary amines was complete in several minutes, affording various nitriles in moderate to good yields.
- Zhang, Jintang,Wang, Zhentao,Wang, Ye,Wan, Changfeng,Zheng, Xiaoqi,Wang, Zhiyong
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supporting information; scheme or table
p. 1973 - 1978
(2010/06/15)
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- Insights into the role of new palladium pincer complexes as robust and recyclable precatalysts for suzuki-miyaura couplings in neat water
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Suzuki-Miyaura biaryl and diarylmethane syntheses via the coupling of arylboronic acids with aryl and arylmethyl bromides are performed in water by means of two new CNC-type palladium pincer complexes. Good to excellent results (including high TON values and extended recycling procedures) are obtained in most cases for a range of electronically dissimilar halides and boronic acids. On the basis of a series of kinetics studies, transmission electron microscopy (TEM), mercury drop tests, and quantitative poisoning experiments, the real role of the latter palladacycles, closely linked to the formation and active participation of palladium nanoparticles, is discussed.
- Ines, Blanca,Sanmartin, Raul,Moure, Maria Jesus,Dominguez, Esther
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experimental part
p. 2124 - 2132
(2009/12/25)
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- High catalytic efficiency of nanostructured molybdenum trioxide in the benzylation of arenes and an investigation of the reaction mechanism
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The synthesis and characterization of nanostructured MoO3 with a thickness of about 30 nm and a width of about 450 nm are reported. The composition formula of the MP (precipitation method) precursor was estimated to be [(NH4)2O]0.169·MoO 3· (H2O)0.239. The calcination of the precursor in air afforded nanostructured pellets of the α-MoO3 phase. The nano-structured MoO3 catalyst exhibited high efficiency in catalyzing the benzylation of various arenes with substituted benzyl alcohols, which were strikingly different to common bulk MoO3. Most reactions offered >99% conversion and >99% selectivity to monoalkylated compounds. MoO3 is a typical acid catalyst. However, the benzylation reaction over nanostructured MoO3 does not belong to the acid-catalyzed type or defect site-catalyzed type, since the catalyst has no acidity and defect site on surface. Characterization with thermal, spectroscopic, and electronic techniques reveal that the catalyst contains fully oxygen-coordinated MoO 6 octahedrons on the surface but partially reduced species (Mo 5+) within the bulk phase. The terminal oxygen atoms of Mo=O bonds on the (010) basal plane resemble oxygen anion radicals and act as active sites for the adsorption and activation of benzyl alcohols by electrophilic attack. Such sites are indispensable for catalytic reactions since the blocking of these sites by electron acceptors, such as tetracyanoethylene (TCNE), can greatly decrease catalytic activity. This work represents a successful example of combining a heterogeneous catalysis study with nanomaterial synthesis.
- Wang, Feng,Ueda, Wataru
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experimental part
p. 742 - 753
(2009/10/01)
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- A nonsymmetric pincer-catalyzed Suzuki-Miyaura arylation of benzyl halides and other nonactivated unusual coupling partners
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(Chemical Equation Presented) The catalytic activity of a PCN-type palladium pincer complex is evaluated in the construction of C(sp 2)-C(sp2) and C(sp2)-C(sp3) bonds by Suzuki-Miyaura cross-couplings employing nontypical substrates such as benzyl halides, α-haloenones, or alkylboronic acids as coupling partners. Most of the reported reactions are achieved in aqueous media, with all of the advantages implied.
- Ines, Blanca,Moreno, Isabel,SanMartin, Raul,Dominguez, Esther
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supporting information; experimental part
p. 8448 - 8451
(2009/04/11)
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- Benzaldimines as ligands for palladium in Suzuki-Miyaura reactions
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Schiff bases derived from substituted benzaldehydes are effective ligands for palladium(0) in the Suzuki-Miyaura coupling of phenylboronic acid with aryl, benzyl and allyl bromides under mild conditions.
- Srimani, Dipankar,Sarkar, Amitabha
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scheme or table
p. 6304 - 6307
(2009/04/06)
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