325142-82-3Relevant academic research and scientific papers
Cross-Coupling through Ag(I)/Ag(III) Redox Manifold
Demonti, Luca,Mézailles, Nicolas,Nebra, Noel,Saffon-Merceron, Nathalie
supporting information, p. 15396 - 15405 (2021/10/12)
In ample variety of transformations, the presence of silver as an additive or co-catalyst is believed to be innocuous for the efficiency of the operating metal catalyst. Even though Ag additives are required often as coupling partners, oxidants or halide scavengers, its role as a catalytically competent species is widely neglected in cross-coupling reactions. Most likely, this is due to the erroneously assumed incapacity of Ag to undergo 2e? redox steps. Definite proof is herein provided for the required elementary steps to accomplish the oxidative trifluoromethylation of arenes through AgI/AgIII redox catalysis (i. e. CEL coupling), namely: i) easy AgI/AgIII 2e? oxidation mediated by air; ii) bpy/phen ligation to AgIII; iii) boron-to-AgIII aryl transfer; and iv) ulterior reductive elimination of benzotrifluorides from an [aryl-AgIII-CF3] fragment. More precisely, an ultimate entry and full characterization of organosilver(III) compounds [K]+[AgIII(CF3)4]? (K-1), [(bpy)AgIII(CF3)3] (2) and [(phen)AgIII(CF3)3] (3), is described. The utility of 3 in cross-coupling has been showcased unambiguously, and a large variety of arylboron compounds was trifluoromethylated via [AgIII(aryl)(CF3)3]? intermediates. This work breaks with old stereotypes and misconceptions regarding the inability of Ag to undergo cross-coupling by itself.
One-pot synthesis of Ag-Cu-Cu2O/C nanocomposites derived from a metal-organic framework as a photocatalyst for borylation of aryl halide
Annas, Dicky,Bae, Jong-Seong,Hira, Shamim Ahmed,Park, Kang Hyun,Park, Sungkyun,Song, Sehwan
, p. 32965 - 32972 (2021/12/07)
Mixed metal-metal oxide/C (Ag-Cu-Cu2O/C) nanocomposites were synthesized by the heat treatment of a metal-organic framework under a N2 flow using the one-pot synthesis method. The as-prepared nanocomposites were characterized using a range of techniques,
Ligand-Enabled, Iridium-Catalyzed ortho-Borylation of Fluoroarenes
Kuleshova, Olena,Asako, Sobi,Ilies, Laurean
, p. 5968 - 5973 (2021/05/31)
A terpyridine derivative and an iridium complex catalyze the C-H borylation of a stoichiometric amount of a fluoroarene with high ortho-selectivity and tolerance of functional groups such as bromide, chloride, ester, ketone, amine, and in situ-borylated hydroxyl. Complex drug molecules such as haloperidol can be selectively borylated ortho to the F atom. The terpyridine ligand undergoes rollover cyclometalation to produce an N,N,C-coordinated iridium complex, which may either selectively borylate the fluoroarene by itself or undergo reductive elimination to produce a borylated ligand.
Transformations of Aryl Ketones via Ligand-Promoted C?C Bond Activation
Dai, Hui-Xiong,Li, Hanyuan,Li, Ling-Jun,Liu, Qi-Sheng,Ma, Biao,Wang, Mei-Ling,Wang, Xing,Wang, Zhen-Yu,Xu, Hui
, p. 14388 - 14393 (2020/07/06)
The coupling of aromatic electrophiles (aryl halides, aryl ethers, aryl acids, aryl nitriles etc.) with nucleophiles is a core methodology for the synthesis of aryl compounds. Transformations of aryl ketones in an analogous manner via carbon–carbon bond activation could greatly expand the toolbox for the synthesis of aryl compounds due to the abundance of aryl ketones. An exploratory study of this approach is typically based on carbon–carbon cleavage triggered by ring-strain release and chelation assistance, and the products are also limited to a specific structural motif. Here we report a ligand-promoted β-carbon elimination strategy to activate the carbon–carbon bonds, which results in a range of transformations of aryl ketones, leading to useful aryl borates, and also to biaryls, aryl nitriles, and aryl alkenes. The use of a pyridine-oxazoline ligand is crucial for this catalytic transformation. A gram-scale borylation reaction of an aryl ketone via a simple one-pot operation is reported. The potential utility of this strategy is also demonstrated by the late-stage diversification of drug molecules probenecid, adapalene, and desoxyestrone, the fragrance tonalid as well as the natural product apocynin.
Visible Light-Induced Borylation of C-O, C-N, and C-X Bonds
Arman, Hadi D.,Dang, Hang. T.,Haug, Graham C.,He, Ru,Jin, Shengfei,Larionov, Oleg V.,Nguyen, Viet D.,Nguyen, Vu T.,Schanze, Kirk S.
supporting information, (2020/02/04)
Boronic acids are centrally important functional motifs and synthetic precursors. Visible light-induced borylation may provide access to structurally diverse boronates, but a broadly efficient photocatalytic borylation method that can effect borylation of a wide range of substrates, including strong C-O bonds, remains elusive. Herein, we report a general, metal-free visible light-induced photocatalytic borylation platform that enables borylation of electron-rich derivatives of phenols and anilines, chloroarenes, as well as other haloarenes. The reaction exhibits excellent functional group tolerance, as demonstrated by the borylation of a range of structurally complex substrates. Remarkably, the reaction is catalyzed by phenothiazine, a simple organic photocatalyst with MW 200 that mediates the previously unachievable visible light-induced single electron reduction of phenol derivatives with reduction potentials as negative as approximately - 3 V versus SCE by a proton-coupled electron transfer mechanism. Mechanistic studies point to the crucial role of the photocatalyst-base interaction.
Hydride Transfer Enables the Nickel-Catalyzed ipso-Borylation and Silylation of Aldehydes
Srimontree, Watchara,Guo, Lin,Rueping, Magnus
supporting information, p. 423 - 427 (2019/12/27)
Nickel-catalyzed ipso-borylations and silylations of aldehydes are described for the first time. The new functional-group interconversion protocol is characterized by its scalability, functional-group tolerance and wide substrate scope, including examples of late-stage functionalization of complex molecules. The key for the successful reaction outcome is the use of a ketone as a hydride acceptor that intercepts the nickel hydride to undergo a reductive pathway, thus allowing formation of the desired C?B and C?Si bonds.
Direct C?H Borylation of Arenes Catalyzed by Saturated Hydride-Boryl-Iridium-POP Complexes: Kinetic Analysis of the Elemental Steps
Esteruelas, Miguel A.,Martínez, Antonio,Oliván, Montserrat,O?ate, Enrique
supporting information, p. 12632 - 12644 (2020/09/09)
The saturated trihydride IrH3{κ3-P,O,P-[xant(PiPr2)2]} (1; xant(PiPr2)2=9,9-dimethyl-4,5-bis(diisopropylphosphino)xanthene) activates the B?H bond of two molecules of pinacolborane (HBpin) to give H2, the hydride-boryl derivatives IrH2(Bpin){κ3-P,O,P-[xant(PiPr2)2]} (2) and IrH(Bpin)2{κ3-P,O,P-[xant(PiPr2)2]} (3) in a sequential manner. Complex 3 activates a C?H bond of two molecules of benzene to form PhBpin and regenerates 2 and 1, also in a sequential manner. Thus, complexes 1, 2, and 3 define two cycles for the catalytic direct C?H borylation of arenes with HBpin, which have dihydride 2 as a common intermediate. C?H bond activation of the arenes is the rate-determining step of both cycles, as the C?H oxidative addition to 3 is faster than to 2. The results from a kinetic study of the reactions of 1 and 2 with HBpin support a cooperative function of the hydride ligands in the B?H bond activation. The addition of the boron atom of the borane to a hydride facilitates the coordination of the B?H bond through the formation of κ1- and κ2-dihydrideborate intermediates.
Redox-Neutral Borylation of Aryl Sulfonium Salts via C-S Activation Enabled by Light
Huang, Chen,Feng, Jie,Ma, Rui,Fang, Shuaishuai,Lu, Tao,Tang, Weifang,Du, Ding,Gao, Jian
, p. 9688 - 9692 (2019/12/02)
Reported here is a novel photoinduced strategy for the borylation of aryl sulfonium salts using bis(pinacolato)diboron as the boron source. This method exploits redox-neutral aryl sulfoniums to gain access to aryl radicals via C-S bond activation upon photoexcitation under transition-metal-free conditions. Therefore, it grants access to diverse arylboronate esters with good performance from easily available aryl sulfoniums accompanied by mild conditions, operational simplicity, and easy scalability.
Group 4 Post-Metallocenes Supported by [OCH2 N,C(σ-aryl)] Auxiliaries Bearing a Seven-Membered Metallacycle: Synthesis, Characterization, and Catalysts for Olefin Polymerization
Liu, Cham-Chuen,Liu, Qian,Yiu, Shek-Man,Chan, Michael C. W.
supporting information, p. 2963 - 2971 (2019/08/22)
A series of pyridine-2-phenolate-6-(σ-aryl) [OCH2 N,C] group 4 bis(benzyl) precatalysts, featuring a flexible O,N-donor chelate, have been prepared and characterized by multinuclear NMR spectroscopy. These complexes adopt C1/su
Additive- and Photocatalyst-Free Borylation of Arylazo Sulfones under Visible Light
Xu, Yuliang,Yang, Xinying,Fang, Hao
, p. 12831 - 12837 (2018/10/20)
We developed a photocatalyst-free and additive-free, visible light induced borylation reaction using arylazo sulfones as starting material. This protocol shows some advantages such as mild conditions, simple equipment, and wide substrate scope, which gives a complementary protocol for the preparation of arylboronates.
