42044-07-5Relevant articles and documents
A photocatalytic ensemble HP-T?Au-Fe3O4: Synergistic and balanced operation in Kumada and Heck coupling reactions
Bhalla, Vandana,Kaur, Harpreet,Kumar, Manoj
supporting information, p. 8036 - 8045 (2020/11/30)
A supramolecular catalytic ensemble HP-T?Au-Fe3O4 supported by highly branched assemblies of hexaphenylbenzene (HPB) derivatives has been developed. The as-prepared HP-T?Au-Fe3O4 nanohybrid material serves as an efficient catalytic system to prepare biaryl derivatives through the Kumada cross-coupling reaction using aryl chlorides as one of the coupling partners under mild reaction conditions (visible light irradiation, aqueous media, aerial conditions, short reaction time). Through the cooperative effect of Au NPs and Fe3O4 NPs, dual activation of aryl chlorides for the generation of aryl radical intermediates is achieved. On the other hand, oligomeric assemblies contributed significantly to the enhancement of the reaction rate and yield of the product by facilitating the reductive elimination step. Different mechanistic studies confirm the involvement of Au NPs, Fe3O4 NPs and oligomeric assemblies in the synergistic and balanced operation of HP-T?Au-Fe3O4 nanohybrid materials in the efficient completion of the catalytic cycle of the Kumada coupling reaction. Being magnetic, the catalytic ensemble could be recycled for up to five catalytic cycles. The as-prepared supramolecular photocatalytic ensemble also works efficiently in Heck coupling reactions involving aryl chlorides and aryl iodides as the coupling partner.
Nickel-catalyzed C-N bond activation: Activated primary amines as alkylating reagents in reductive cross-coupling
Yue, Huifeng,Zhu, Chen,Shen, Li,Geng, Qiuyang,Hock, Katharina J.,Yuan, Tingting,Cavallo, Luigi,Rueping, Magnus
, p. 4430 - 4435 (2019/04/29)
Nickel-catalyzed reductive cross coupling of activated primary amines with aryl halides under mild reaction conditions has been achieved for the first time. Due to the avoidance of stoichiometric organometallic reagents and external bases, the scope regarding both coupling partners is broad. Thus, a wide range of substrates, natural products and drugs with diverse functional groups are tolerated. Moreover, experimental mechanistic investigations and density functional theory (DFT) calculations in combination with wavefunction analysis have been performed to understand the catalytic cycle in more detail.
Ni-Catalyzed cross-coupling of aryl thioethers with alkyl Grignard reagents via C-S bond cleavage
Zhu, Dan,Shi, Lei
supporting information, p. 9313 - 9316 (2018/08/29)
A Ni-catalyzed cross-coupling of aryl thioethers with alkyl Grignard reagents, accompanied by the cleavage of the C(aryl)-SMe bond, has been presented. This method is distinguished by its mild conditions and moderate functional group tolerance, such as hydroxyl, halogen, and heterocycles, which should provide a straightforward access to the modification of sulfur-containing molecules.
Ionic iron(III) complexes bearing a dialkylbenzimidazolium cation: Efficient catalysts for magnesium-mediated cross-couplings of aryl phosphates with alkyl bromides
Li, Zhuang,Lu, Bing,Sun, Hongmei,Shen, Qi,Zhang, Yong
, (2017/07/24)
A series of ionic iron(III) complexes of general formula [HLn][FeX4] (HL1?=?1,3-dibenzylbenzimidazolium cation, X?=?Cl, 1; HL1, X?=?Br, 2; HL2?=?1,3-dibutylbenzimidazolium cation, X?=?Br, 3; HL3?=?1,3-bis(diphenylmethyl)benzimidazolium cation, X?=?Br, 4) were easily prepared in high yields by the direct reaction of FeX3 with 1 equiv. of [HLn]X under mild conditions. All of them were characterized using elemental analysis, Raman spectroscopy and electrospray ionization mass spectrometry, and X-ray crystallography for 1 and 4. In the presence of magnesium turnings and LiCl, these air- and moisture-insensitive complexes showed high catalytic activities in direct cross-couplings of aryl phosphates with primary and secondary alkyl bromides with broad substrate scope, wherein complex 4 was the most effective.
Nickel-Catalyzed C-O Bond-Cleaving Alkylation of Esters: Direct Replacement of the Ester Moiety by Functionalized Alkyl Chains
Liu, Xiangqian,Jia, Jiaqi,Rueping, Magnus
, p. 4491 - 4496 (2017/07/24)
Two efficient protocols for the nickel-catalyzed aryl-alkyl cross-coupling reactions using esters as coupling components have been established. The methods enable the selective oxidative addition of nickel to acyl C-O and aryl C-O bonds and allow the aryl-alkyl cross-coupling via decarbonylative bond cleavage or through cleavage of a C-O bond with high efficiency and good functional group compatibility. The protocols allow the streamlined, unconventional utilization of widespread ester groups and their precursors, carboxylic acids and phenols, in synthetic organic chemistry.
Nickel-Catalyzed Reductive Cross-Coupling of Aryl Triflates and Nonaflates with Alkyl Iodides
Sumida, Yuto,Sumida, Tomoe,Hosoya, Takamitsu
, p. 3590 - 3601 (2017/08/16)
A nickel-catalyzed cross-electrophile coupling of aryl triflates and nonaflates with alkyl iodides using manganese(0) as a reductant is described. The method is applicable to the reductive alkylation of various aryl sulfonates, including o -borylaryl triflate, which enabled efficient construction of diverse alkylated arenes under mild conditions.
Manganese-Mediated C?H Alkylation of Unbiased Arenes Using Alkylboronic Acids
Castro, Susana,Fernández, Juan J.,Fa?anás, Francisco J.,Vicente, Rubén,Rodríguez, Félix
supporting information, p. 9068 - 9071 (2016/07/14)
The alkylation of arenes is an essential synthetic step of interest not only from the academic point of view but also in the bulk chemical industry. Despite its limitations, the Friedel–Crafts reaction is still the method of choice for most of the arene alkylation processes. Thus, the development of new strategies to synthesize alkyl arenes is a highly desirable goal, and herein, we present an alternative method to those conventional reactions. Particularly, a simple protocol for the direct C?H alkylation of unbiased arenes with alkylboronic acids in the presence of Mn(OAc)3?2H2O is reported. Primary or secondary unactivated alkylboronic acids served as alkylating agents for the direct functionalization of representative polyaromatic hydrocarbons (PAHs) or benzene. The results are consistent with a free-radical mechanism.
Nickel-catalyzed alkylative cross-coupling of anisoles with grignard reagents via C-O bond activation
Tobisu, Mamoru,Takahira, Tsuyoshi,Morioka, Toshifumi,Chatani, Naoto
supporting information, p. 6711 - 6714 (2016/06/14)
We report nickel-catalyzed cross-coupling of methoxyarenes with alkylmagnesium halides, in which a methoxy group is eliminated. A wide range of alkyl groups, including those bearing β-hydrogens, can be introduced directly at the ipso position of anisole derivatives. We demonstrate that the robustness of a methoxy group allows this alkylation protocol to be used to synthesize elaborate molecules by combining it with traditional cross-coupling reactions or oxidative transformation. The success of this method is dependent on the use of alkylmagnesium iodides, but not chlorides or bromides, which highlights the importance of the halide used in developing catalytic reactions using Grignard reagents.
Alkylations of Arylboronic Acids including Difluoroethylation/Trifluoroethylation via Nickel-Catalyzed Suzuki Cross-Coupling Reaction
Zhang, Xiaofei,Yang, Chunhao
supporting information, p. 2721 - 2727 (2015/09/01)
An efficient alkylation method of functionalized alkyl halides under mild nickel-catalyzed C(sp3)-(sp2) Suzuki cross-coupling conditions is described. The features of this approach are excellent functional group compatibility, low cost nickel catalyst, and the use of a mild base. This is also the first successful example of the nickel-catalyzed direct 2,2-difluoroethylation or 2,2,2-trifluoroethylation of aryl-/heteroarylboronic acids.
Synthesis, spectral and structural characterization of Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) complexes with 2-mercapto-5-methyl-1,3,4-thiadiazole: A Zn(II) complex acting as a new sensitive and selective fluorescent probe for the detection of Hg2+ in H2O-MeOH medium
Bharati, Pooja,Bharti,Bharty,Kashyap,Singh,Singh
, p. 222 - 231 (2013/10/22)
Five new complexes, [Ni(mthd)2(py)2] (1), [Cu(en)2](mthd)2 (2), [H2en][Hg(mthd) 3]2·2H2O (3), [Cd (mthd) 2(o-phen)2]2·H2O (4) and [Zn(mthd)2(bpy)] (5) (Hmthd = 2-mercapto-5-methyl-1,3,4-thiadiazole), have been synthesized. All the complexes have been fully characterized by various techniques: elemental analyses, IR, electronic and fluorescent spectral data. The ligand is present in the deprotonated thiol form in the complexes [Cu(en)2](mthd)2(2)and [Cd(mthd)2(o-phen) 2]2·H2O(4). In complex 2, the ligand isionically bonded, whereas it is covalently bonded through the sulfur in complex 4. In [Ni(mthd)2(py)2] (1) the ligand is N, S chelating bidentate bonded through the thiol sulfur and the thiadiazole ring nitrogen adjacent to it, forming a four membered chelate ring. The ligand is covalently bonded through the deprotonated thiadiazole ring nitrogen adjacent to the thiol sulfur in [Zn(mthd)2(bpy)] (5). The complex anion in [H2en][Hg(mthd)3]2·2H2O (3) has a triangular planar geometry, with bonding through the deprotonated thiolato sulfur atoms from the three ligands. [Zn(mthd)2(bpy)] (5) is highly fluorescent as compared to the other complexes and has been further used as a metal probe for sensing of Hg2+ in H2O-MeOH solution. Complex 5, upon interaction with Hg2+, shows a hypochromic shift in the absorption spectra whereas the emission spectra exhibited 75% quenching fluorescence behavior. The electrochemical studies also suggest the interaction of Hg(II) with the Zn(II) complex, probably via the free thione sulfur.
