380481-66-3Relevant articles and documents
Nickel-Catalyzed Regioselective Alkenylarylation of γ,δ-Alkenyl Ketones via Carbonyl Coordination
Aryal, Vivek,Dhungana, Roshan K.,Giri, Ramesh,Lakomy, Margaret G.,Niroula, Doleshwar,Sapkota, Rishi R.
supporting information, p. 19092 - 19096 (2021/08/09)
We disclose a nickel-catalyzed reaction, which enabled us to difunctionalize unactivated γ,δ-alkenes in ketones with alkenyl triflates and arylboronic esters. The reaction was made feasible by the use of 5-chloro-8-hydroxyquinoline as a ligand along with
Ni-Catalyzed Borylation of Aryl Sulfoxides
Huang, Mingming,Wu, Zhu,Krebs, Johannes,Friedrich, Alexandra,Luo, Xiaoling,Westcott, Stephen A.,Radius, Udo,Marder, Todd B.
supporting information, p. 8149 - 8158 (2021/05/10)
A nickel/N-heterocyclic carbene (NHC) catalytic system has been developed for the borylation of aryl sulfoxides with B2(neop)2 (neop=neopentyl glycolato). A wide range of aryl sulfoxides with different electronic and steric properties were converted into the corresponding arylboronic esters in good yields. The regioselective borylation of unsymmetric diaryl sulfoxides was also feasible leading to borylation of the sterically less encumbered aryl substituent. Competition experiments demonstrated that an electron-deficient aryl moiety reacts preferentially. The origin of the selectivity in the Ni-catalyzed borylation of electronically biased unsymmetrical diaryl sulfoxide lies in the oxidative addition step of the catalytic cycle, as oxidative addition of methoxyphenyl 4-(trifluoromethyl)phenyl sulfoxide to the Ni(0) complex occurs selectively to give the structurally characterized complex trans-[Ni(ICy)2(4-CF3-C6H4){(SO)-4-MeO-C6H4}] 4. For complex 5, the isomer trans-[Ni(ICy)2(C6H5)(OSC6H5)] 5-I was structurally characterized in which the phenyl sulfinyl ligand is bound via the oxygen atom to nickel. In solution, the complex trans-[Ni(ICy)2(C6H5)(OSC6H5)] 5-I is in equilibrium with the S-bonded isomer trans-[Ni(ICy)2(C6H5)(SOC6H5)] 5, as shown by NMR spectroscopy. DFT calculations reveal that these isomers are separated by a mere 0.3 kJ/mol (M06/def2-TZVP-level of theory) and connected via a transition state trans-[Ni(ICy)2(C6H5)(η2-{SO}-C6H5)], which lies only 10.8 kcal/mol above 5.
Unveiling Extreme Photoreduction Potentials of Donor-Acceptor Cyanoarenes to Access Aryl Radicals from Aryl Chlorides
Cao, Jilei,Tang, Xinxin,Toh, Ren Wei,Wang, Han,Wu, Jie,Wu, Xiangyang,Xu, Jinhui,Yang, Xiaona,Yeow, Edwin K. L.,Zhou, Rong
supporting information, p. 13266 - 13273 (2021/09/07)
Since the seminal work of Zhang in 2016, donor-acceptor cyanoarene-based fluorophores, such as 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN), have been widely applied in photoredox catalysis and used as excellent metal-free alternatives to noble metal Ir- and Ru-based photocatalysts. However, all the reported photoredox reactions involving this chromophore family are based on harnessing the energy from a single visible light photon, with a limited range of redox potentials from -1.92 to +1.79 V vs SCE. Here, we document the unprecedented discovery that this family of fluorophores can undergo consecutive photoinduced electron transfer (ConPET) to achieve very high reduction potentials. One of the newly synthesized catalysts, 2,4,5-tri(9H-carbazol-9-yl)-6-(ethyl(phenyl)amino)isophthalonitrile (3CzEPAIPN), possesses a long-lived (12.95 ns) excited radical anion form, 3CzEPAIPN?-*, which can be used to activate reductively recalcitrant aryl chlorides (Ered ≈ -1.9 to -2.9 V vs SCE) under mild conditions. The resultant aryl radicals can be engaged in synthetically valuable aromatic C-B, C-P, and C-C bond formation to furnish arylboronates, arylphosphonium salts, arylphosphonates, and spirocyclic cyclohexadienes.
Ruthenium-Catalyzed Carbonylative Coupling of Anilines with Organoboranes by the Cleavage of Neutral Aryl C-N Bond
Xu, Jian-Xing,Zhao, Fengqian,Yuan, Yang,Wu, Xiao-Feng
supporting information, p. 2756 - 2760 (2020/03/30)
Herein, we report the first ruthenium-catalyzed Suzuki-type carbonylative reaction of electronically neutral anilines via C(aryl)-N bond cleavage. Without any ligand and base, diaryl ketones can be obtained in moderate to high yields by using Ru3/su
Small Phosphine Ligands Enable Selective Oxidative Addition of Ar-O over Ar-Cl Bonds at Nickel(0)
Entz, Emily D.,Hooker, Leidy V.,Neufeldt, Sharon R.,Russell, John E. A.
supporting information, p. 15454 - 15463 (2020/10/18)
Current methods for Suzuki-Miyaura couplings of nontriflate phenol derivatives are limited by their intolerance of halides including aryl chlorides. This is because Ni(0) and Pd(0) often undergo oxidative addition of organohalides at a similar or faster rate than most Ar-O bonds. DFT and stoichiometric oxidative addition studies demonstrate that small phosphines, in particular PMe3, are unique in promoting preferential reaction of Ni(0) with aryl tosylates and other C-O bonds in the presence of aryl chlorides. This selectivity was exploited in the first Ni-catalyzed C-O-selective Suzuki-Miyaura coupling of chlorinated phenol derivatives where the oxygen-containing leaving group is not a fluorinated sulfonate such as triflate. Computational studies suggest that the origin of divergent selectivity between PMe3 and other phosphines differs from prior examples of ligand-controlled chemodivergent cross-couplings. PMe3 effects selective reaction at tosylate due to both electronic and steric factors. A close interaction between nickel and a sulfonyl oxygen of tosylate during oxidative addition is critical to the observed selectivity.
Visible-Light-Induced Ni-Catalyzed Radical Borylation of Chloroarenes
Tian, Ya-Ming,Guo, Xiao-Ning,Krummenacher, Ivo,Wu, Zhu,Nitsch, J?rn,Braunschweig, Holger,Radius, Udo,Marder, Todd B.
supporting information, p. 18231 - 18242 (2020/11/02)
A highly selective and general photoinduced C-Cl borylation protocol that employs [Ni(IMes)2] (IMes = 1,3-dimesitylimidazoline-2-ylidene) for the radical borylation of chloroarenes is reported. This photoinduced system operates with visible light (400 nm) and achieves borylation of a wide range of chloroarenes with B2pin2 at room temperature in excellent yields and with high selectivity, thereby demonstrating its broad utility and functional group tolerance. Mechanistic investigations suggest that the borylation reactions proceed via a radical process. EPR studies demonstrate that [Ni(IMes)2] undergoes very fast chlorine atom abstraction from aryl chlorides to give [NiI(IMes)2Cl] and aryl radicals. Control experiments indicate that light promotes the reaction of [NiI(IMes)2Cl] with aryl chlorides generating additional aryl radicals and [NiII(IMes)2Cl2]. The aryl radicals react with an anionic sp2-sp3 diborane [B2pin2(OMe)]- formed from B2pin2 and KOMe to yield the corresponding borylation product and the [Bpin(OMe)]?- radical anion, which reduces [NiII(IMes)2Cl2] under irradiation to regenerate [NiI(IMes)2Cl] and [Ni(IMes)2] for the next catalytic cycle.
Oxidatively Induced Reductive Elimination: Exploring the Scope and Catalyst Systems with Ir, Rh, and Ru Complexes
Kim, Jinwoo,Shin, Kwangmin,Jin, Seongho,Kim, Dongwook,Chang, Sukbok
supporting information, p. 4137 - 4146 (2019/03/07)
Direct conversion of C-H bonds into C-C bonds is a promising alternative to the conventional cross-coupling reactions, thus giving rise to a wide range of efficient catalytic C-H functionalization reactions. Among the elementary stages in the catalytic C-
Ruthenium-Catalyzed Reductive Arylation of N-(2-Pyridinyl)amides with Isopropanol and Arylboronate Esters
Ronson, Thomas O.,Renders, Evelien,Van Steijvoort, Ben F.,Wang, Xubin,Wybon, Clarence C. D.,Prokopcová, Hana,Meerpoel, Lieven,Maes, Bert U. W.
supporting information, p. 482 - 487 (2019/01/04)
A new three-component reductive arylation of amides with stable reactants (iPrOH and arylboronate esters), making use of a 2-pyridinyl (Py) directing group, is described. The N-Py-amide substrates are readily prepared from carboxylic acids and PyNH2, and the resulting N-Py-1-arylalkanamine reaction products are easily transformed into the corresponding chlorides by substitution of the HN-Py group with HCl. The 1-aryl-1-chloroalkane products allow substitution and cross-coupling reactions. Therefore, a general protocol for the transformation of carboxylic acids into a variety of functionalities is obtained. The Py-NH2 by-product can be recycled.
Copper-catalysed borylation of aryl chlorides
Kuehn, Laura,Huang, Mingming,Radius, Udo,Marder, Todd B.
supporting information, p. 6601 - 6606 (2019/07/16)
We report herein the first Cu-catalysed borylation of a wide range of aryl chlorides with different electronic and steric properties using a readily prepared NHC-stabilised Cu catalyst and KOtBu as the base with B2pin2 (pin = pinacolato) as the boron reagent. The aryl chlorides are converted into their corresponding arylboronic esters in good yields. The new procedure shows broad functional group tolerance, and B2neop2 (neop = neopentyl glycolato) can also be applied as the boron reagent.
Visible light-promoted formation of C-B and C-S bonds under metal- A nd photocatalyst-free conditions
Blank, Lena,Fagnoni, Maurizio,Protti, Stefano,Rueping, Magnus
, p. 1243 - 1252 (2019/02/26)
A green, efficient, photoinduced synthesis of arylboronic esters and aryl sulfides has been developed. Bench stable arylazo sulfones were used as radical precursors for a photocatalyst- A nd additive-free carbon-heteroatom bond formation under visible light. The protocols are applicable to a wide range of substrates, providing products in good yields.
