75722-64-4Relevant academic research and scientific papers
Cobalt-Catalyzed Kumada Coupling Forming Sterically Encumbered C-C Bonds
Brennan, Marshall R.,Darrow, William T.,Fout, Alison R.,Killion, Jack A.,Leahy, Clare A.
, (2021/12/02)
A Co(acac)3/PN precatalyst was developed and optimized for catalytic Kumada coupling of aryl Grignard reagents to sterically encumbered alkyl halides. The substrate scope demonstrates excellent yields for primary alkyl chlorides and bromides, including good performance using neopentyl chloride and neophyl chloride. Secondary alkyl halides were also successfully arylated in good yields, and the presence of β-hydrogen atoms in a substrate did not inhibit product formation. An intermolecular functional group tolerance screen was conducted which indicates that ester and amide functionality are well tolerated by the reaction conditions. Electrophiles containing ester, pyridine, and nitrile functionality were all coupled with 2-mesitylmagnesium bromide in good yields, supporting tolerance screen results. The intermolecular screen also showed that functional groups which are typically reactive with Grignard reagents such as alcohols and terminal alkynes were not well-tolerated by the reaction.
Highly Chemoselective Deoxygenation of N-Heterocyclic N-Oxides Using Hantzsch Esters as Mild Reducing Agents
An, Ju Hyeon,Kim, Kyu Dong,Lee, Jun Hee
supporting information, p. 2876 - 2894 (2021/02/01)
Herein, we disclose a highly chemoselective room-temperature deoxygenation method applicable to various functionalized N-heterocyclic N-oxides via visible light-mediated metallaphotoredox catalysis using Hantzsch esters as the sole stoichiometric reductant. Despite the feasibility of catalyst-free conditions, most of these deoxygenations can be completed within a few minutes using only a tiny amount of a catalyst. This technology also allows for multigram-scale reactions even with an extremely low catalyst loading of 0.01 mol %. The scope of this scalable and operationally convenient protocol encompasses a wide range of functional groups, such as amides, carbamates, esters, ketones, nitrile groups, nitro groups, and halogens, which provide access to the corresponding deoxygenated N-heterocycles in good to excellent yields (an average of an 86.8% yield for a total of 45 examples).
Palladium (II) Complexes Containing 2-Phenylpyridine Derivatives: Synthesis, Molecular Structures, and Catalytic Activity for Suzuki–Miyaura Cross-Coupling Reactions
Adamson, A.,Alhaddad, M. R.,Arshad, M. N.,Asiri, A. M.,Budiman, Y. P.,Mkhalid, I.,Muhammad, R.
, p. 466 - 475 (2020/07/31)
The preparation and characterization of a series of new 2-phenylpyridine derivative ligands consisting of 2-(R) pyridine (R = mesityl (L1), 2,6-dimethylphenyl (L2), o-tolyl (L3), m-tolyl (L4), p-tolyl (L5), o-methoxyphenyl (L6), and p-methoxyphenyl (L7)) and their Pd complexes [PdCl2L2] (L1–L7) is investigated using a combination of X-ray diffraction spectroscopy, GC-MS, and NMR. The crystal structures show that the Pd complexes adopt a square planar geometry, and the monodentate ligand is coordinated through the N donor of the pyridine ring to the Pd atom. The catalytic activities of the synthesized complexes are investigated. The square planar Pd complex trans-[(2-mesitylpy)2PdCl2)] shows a high efficiency in promoting Suzuki-Miyaura cross coupling in an aqueous solvent under aerobic conditions.
Generation of Aryl Radicals from Aryl Halides: Rongalite-Promoted Transition-Metal-Free Arylation
Yu, Fazhi,Mao, Runyu,Yu, Mingcheng,Gu, Xianfeng,Wang, Yonghui
, p. 9946 - 9956 (2019/09/04)
A new and practical method for the generation of aryl radicals from aryl halides is reported. Rongalite as a novel precursor of super electron donors was used to initiate a series of electron-catalyzed reactions under mild conditions. These transition-metal-free radical chain reactions enable the efficient formation of C-C, C-S, and C-P bonds through homolytic aromatic substitution or SRN1 reactions. Moreover, the synthesis of antipsychotic drug Quetiapine was performed on gram scale through the described method. This protocol demonstrated its potential as a promising arylation method in organic synthesis.
Palladium-Catalyzed Electrochemical C-H Alkylation of Arenes
Yang, Qi-Liang,Li, Chuan-Zeng,Zhang, Liang-Wei,Li, Yu-Yan,Tong, Xiaofeng,Wu, Xin-Yan,Mei, Tian-Sheng
, p. 1208 - 1212 (2018/10/20)
Palladium-catalyzed electrochemical C-H functionalization reactions have emerged as attractive tools for organic synthesis. This process offers an alternative to conventional methods that require harsh chemical oxidants. However, this electrolysis requires divided cells to avoid catalyst deactivation by cathodic reduction. Herein, we report the first example of palladium-catalyzed electrochemical C-H alkylation of arenes using undivided electrochemical cells in water, thereby providing a practical solution for the introduction of alkyl groups into arenes.
Triorganoindium reagents in Rh-catalyzed C–H activation/C–C cross-coupling reactions of 2-arylpyridines
Riveiros, Ricardo,Tato, Rubén,Sestelo, José Pérez,Sarandeses, Luis A
, (2018/07/13)
The activation of C–H bonds through catalytic reactions using transition metals is an important challenge in organic chemistry in which the intermediates are related to those produced in the classical cross-coupling reactions. As part of our research program devoted to the development of metal-catalyzed reactions using indium organometallics, a protocol for the C–H activation and C–C coupling of 2-arylpyridines with triorganoindium reagents under Rh(I) catalysis is reported. Under the optimized conditions, we found that Me3In and Ar3In reagents reacted with 2-arylpyridines and related compounds in the presence of Rh(PPh3)3Cl, in PhCl/THF (9:1), at 120?C for 48 h, to afford the ortho-coupling products in moderate to good yields. The nitrogen atom in the pyridine ring acts as a directing group to assist the functionalization at the ortho position of the aryl group forming a new C–C bond at this position.
In Situ Generation of ArCu from CuF2 Makes Coupling of Bulky Aryl Silanes Feasible and Highly Efficient
Delpozo, Juan,Casares, Juan A.,Espinet, Pablo
supporting information, p. 4274 - 4284 (2016/03/16)
A bimetallic system of Pd/CuF2, catalytic in Pd and stoichiometric in Cu, is very efficient and selective for the coupling of fairly hindered aryl silanes with aryl, anisyl, phenylaldehyde, p-cyanophenyl, p-nitrophenyl, or pyridyl iodides of conventional size. The reaction involves the activation of the silane by CuII, followed by disproportionation and transmetalation from the CuI(aryl) to PdII, upon which coupling takes place. CuIII formed during disproportionation is reduced to CuI(aryl) by excess aryl silane, so that the CuF2 system is fully converted into CuI(aryl) and used in the coupling. Moreover, no extra source of fluoride is needed. Interesting size selectivity towards coupling is found in competitive reactions of hindered aryl silanes. Easily accessible [PdCl2(IDM)(AsPh3)] (IDM = 1,3-dimethylimidazol-2-ylidene) is by far the best catalyst, and the isolated products are essentially free from As or Pd (2: In the Cu-promoted Hiyama process, CuF2 plays the role of two reagents to provide full conversion into the fluoride and copper is also required to transform bulky trialkoxysilanes in situ into CuAr. CuAr immediately transmetalates to Pd, which makes the otherwise inaccessible Pd-catalyzed coupling of bulky arylsilanes feasible and highly efficient.
General suzuki coupling of heteroaryl bromides by using tri-tert-butylphosphine as a supporting ligand
Zou, Yinjun,Yue, Guizhou,Xu, Jianwei,Zhou, Jianrong
supporting information, p. 5901 - 5905 (2015/03/30)
A general procedure for the fast Suzuki coupling of major families of heteroaryl bromides was realized by using Pd(OAc)2/PtBu3 as the catalyst. Many couplings were finished within minutes at room temperature in n-butanol. Different from previous studies, three typical heteroaryl bromides were systematically examined in couplings of various heteroaryl and aryl boronic acids. A fast, general coupling of heteroaryl bromides is realized by using a single palladium catalyst supported by tri-tert-butylphosphine.
Expanded ring diaminocarbene palladium complexes: Synthesis, structure, and Suzuki-Miyaura cross-coupling of heteroaryl chlorides in water
Kolychev, Eugene L.,Asachenko, Andrey F.,Dzhevakov, Pavel B.,Bush, Alexander A.,Shuntikov, Viacheslav V.,Khrustalev, Victor N.,Nechaev, Mikhail S.
, p. 6859 - 6866 (2013/08/25)
A series of new 6- and 7-membered N-heterocyclic carbene (NHC) complexes of palladium (NHC)Pd(cinn)Cl (cinn = cinnamyl = 3-phenylallyl) were synthesized and characterized structurally in the solid state. The influence of ring size (5, 6 or 7) and bulkiness of N-aryl substituents (Mes = 2,4,6-trimethylphenyl, or Dipp = 2,6-diisopropylphenyl) in carbenes on palladium catalysed Suzuki-Miyaura cross-coupling was revealed. Due to the unique stereoelectronic properties of expanded ring NHCs, a versatile, highly efficient green protocol of coupling of heteroaromatic chlorides and bromides with boronic acids has been developed. High quantitative yields of biaryls were achieved with water as solvent, under air, using low catalyst and phase transfer agent loadings, and with mild and environmentally benign base NaHCO3. The Royal Society of Chemistry 2013.
Sequential protocol for C(sp3)-H carboxylation with CO 2: Transition-metal-catalyzed benzylic C-H silylation and fluoride-mediated carboxylation
Mita, Tsuyoshi,Michigami, Kenichi,Sato, Yoshihiro
supporting information; body text, p. 3462 - 3465 (2012/08/08)
One of the most challenging transformations in current organic chemistry is the catalytic carboxylation of a C(sp3)-H bond using CO2 gas, an inexpensive and ubiquitous C1 source. A sequential protocol for C(sp3)-H carboxylation by employing a nitrogen-directed, metal-assisted, C-H activation/catalytic silylation reaction in conjunction with fluoride-mediated carboxylation with CO2 was established. The carboxylation proceeded only at the benzylic C(sp3)-Si bond, not at the aromatic C(sp2)-Si, which is advantageous for further manipulations of the products.
