- Mono-Phosphine Metal-Organic Framework-Supported Cobalt Catalyst for Efficient Borylation Reactions
-
We report a metal-organic framework (MOF) supported monoligated phosphine-cobalt complex, which is an active heterogeneous catalyst for aromatic C?H borylation and alkene hydroboration. The mono(phosphine)-Co catalyst (MOF?P?Co) was prepared by metalation of a porous triarylphosphine-functionalized MOF (MOF?P) with CoCl2 followed by activation with NaEt3BH. The MOF catalyst has a broad substrate scope with excellent functional group tolerance to afford arene- and alkyl-boronate esters in excellent yields and selectivity. MOF?P?Co gave a turnover number (TON) of 30,000 and could be recycled and reused at least 13 times in arene C?H borylation. Importantly, the attempt to prepare the homogeneous control (Ph3P?Co) using triphenylphosphine was unsuccessful due to the facile disproportionation reactions or intermolecular ligand exchanges in the solution. In contrast, the site isolation of the active mono(phosphine)-Co species within the MOF affords the robust and coordinatively unsaturated metal complexes, allowing to explore their catalytic properties and the reaction mechanism.
- Akhtar, Naved,Antil, Neha,Balendra,Begum, Wahida,Chauhan, Manav,Gupta, Poorvi,Kumar, Ajay,Malik, Jaideep,Manna, Kuntal,Newar, Rajashree
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supporting information
(2022/03/15)
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- Photochemical and electrochemical C-N borylation of arylhydrazines
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The C-N borylation of arylhydrazine hydrochlorides with bis(pinacolato)diboron was achieved under photochemical and electrochemical conditions, respectively. This novel and scalable transformation provides two efficient and mild transition-metal-free synt
- Du, Linlin,Sun, Li,Zhang, Hua
-
supporting information
p. 1716 - 1719
(2022/02/21)
-
- Synthesis of arylboronates via the Pd-catalyzed desulfitative coupling reaction of sodium arylsulfinates with bis(pinacolato)diboron
-
The desulfitative borylation reaction of sodium arylsulfinates with bis(pinacolato)diboron or bis(neopentylglycolato)diboron under palladium catalysis has been developed, allowing selective C-B bond formation to give arylboronates with a range of functional groups in moderate to good yields under mild reaction conditions. A gram-scale preparation as well as the cascade Suzuki-Miyaura cross-coupling of arylboronates demonstrated the potential practical utility in organic synthesis.
- Qiu, Di,Li, Songyi,Yue, Guanglu,Mao, Jinshan,Xu, Bei,Yuan, Xinyu,Ye, Fei
-
-
- Ligand-Enabled, Iridium-Catalyzed ortho-Borylation of Fluoroarenes
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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.
- Kuleshova, Olena,Asako, Sobi,Ilies, Laurean
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p. 5968 - 5973
(2021/05/31)
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- Undirected ortho-selectivity in C–H borylation of arenes catalyzed by NHC platinum(0) complexes
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Borylation of arenes with bis(pinacolato)diboron catalyzed by sterically encumbered NHC platinum complexes proceeds predominantly at ortho-position even in the absence of a directing group (o: m: p ratio up to 10: 3: 1). The similar borylation with pinacolborane would proceed less selectively.
- Rzhevskiy, Sergey A.,Topchiy, Maxim A.,Golenko, Yulia D.,Gribanov, Pavel S.,Sterligov, Grigorii K.,Kirilenko, Nikita Yu.,Ageshina, Alexandra A.,Bermeshev, Maxim V.,Nechaev, Mikhail S.,Asachenko, Andrey F.
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p. 569 - 571
(2020/10/09)
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- Transformations of Aryl Ketones via Ligand-Promoted C?C Bond Activation
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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.
- Dai, Hui-Xiong,Li, Hanyuan,Li, Ling-Jun,Liu, Qi-Sheng,Ma, Biao,Wang, Mei-Ling,Wang, Xing,Wang, Zhen-Yu,Xu, Hui
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p. 14388 - 14393
(2020/07/06)
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- Borylation of Diazonium Salts by Highly Emissive and Crystalline Carbon Dots in Water
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Efficient borylation reaction of diazonium salts in water is realized for the first time by using easily prepared, highly emissive and crystalline carbon dots. Electron-donating and electron-withdrawing groups on diazonium salts were well tolerated with moderate to good conversion efficiency. Compared with widely used metal complexes, organic dyes and quantum dots, the approach presented herein uses carbon dots, which are nontoxic and possess good biological and medicinal compatibility and high reactivity. Therefore, this approach presents a new prospective use for carbon dots in green chemistry.
- Lei, Tao,Wei, Si-Meng,Feng, Ke,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
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p. 1715 - 1719
(2020/03/23)
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- Visible Light-Induced Borylation of C-O, C-N, and C-X Bonds
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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.
- 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.
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supporting information
(2020/02/04)
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- Selectivity and Physicochemical Optimization of Repurposed Pyrazolo[1,5- b]pyridazines for the Treatment of Human African Trypanosomiasis
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From a high-throughput screen of 42 44 known human kinases inhibitors, a pyrazolo[1,5-b]pyridazine scaffold was identified to begin optimization for the treatment of human African trypanosomiasis. Previously reported data for analogous compounds against h
- Tear, Westley F.,Bag, Seema,Diaz-Gonzalez, Rosario,Ceballos-Pérez, Gloria,Rojas-Barros, Domingo I.,Cordon-Obras, Carlos,Pérez-Moreno, Guiomar,García-Hernández, Raquel,Martinez-Martinez, Maria Santos,Ruiz-Perez, Luis Miguel,Gamarro, Francisco,Gonzalez Pacanowska, Dolores,Caffrey, Conor R.,Ferrins, Lori,Manzano, Pilar,Navarro, Miguel,Pollastri, Michael P.
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p. 756 - 783
(2020/02/04)
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- Controllable factors of supported IR complex catalysis for aromatic C?H borylation
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We have developed a catalyst in which an Ir complex and organic functionalities are coimmobilized on the silica surface. The catalytic activity for aromatic C?H borylation was significantly affected by (i) the linker length of the Ir?bipyridine complex, (ii) the coimmobilized organic functionality, and (iii) the substituents on the aromatic substrate compounds. The fine-tuned supported catalyst showed higher activity than the homogeneous Ir?bipyridine complex when using a specific substrate such as benzonitrile. We elucidated this property by conducting solid-state NMR, FT-IR, XAFS, and in situ FT-IR analysis.
- Chun, Wang-Jae,Maeda, Kyogo,Manaka, Yuichi,Motokura, Ken,Nakajima, Kiyotaka,Satter, Shazia Sharmin,Uemura, Yohei
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p. 14552 - 14559
(2020/12/21)
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- Direct C?H Borylation of Arenes Catalyzed by Saturated Hydride-Boryl-Iridium-POP Complexes: Kinetic Analysis of the Elemental Steps
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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.
- Esteruelas, Miguel A.,Martínez, Antonio,Oliván, Montserrat,O?ate, Enrique
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supporting information
p. 12632 - 12644
(2020/09/09)
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- Discovery of S64315, a Potent and Selective Mcl-1 Inhibitor
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Myeloid cell leukemia 1 (Mcl-1) has emerged as an attractive target for cancer therapy. It is an antiapoptotic member of the Bcl-2 family of proteins, whose upregulation in human cancers is associated with high tumor grade, poor survival, and resistance to chemotherapy. Here we report the discovery of our clinical candidate S64315, a selective small molecule inhibitor of Mcl-1. Starting from a fragment derived lead compound, we have conducted structure guided optimization that has led to a significant (3 log) improvement of target affinity as well as cellular potency. The presence of hindered rotation along a biaryl axis has conferred high selectivity to the compounds against other members of the Bcl-2 family. During optimization, we have also established predictive PD markers of Mcl-1 inhibition and achieved both efficient in vitro cell killing and tumor regression in Mcl-1 dependent cancer models. The preclinical candidate has drug-like properties that have enabled its development and entry into clinical trials.
- Szlavik, Zoltan,Csekei, Marton,Paczal, Attila,Szabo, Zoltan B.,Sipos, Szabolcs,Radics, Gabor,Proszenyak, Agnes,Balint, Balazs,Murray, James,Davidson, James,Chen, Ijen,Dokurno, Pawel,Surgenor, Allan E,Daniels, Zoe Marie,Hubbard, Roderick E.,Le Toumelin-Braizat, Ga?tane,Claperon, Audrey,Lysiak-Auvity, Ga?lle,Girard, Anne-Marie,Bruno, Alain,Chanrion, Maia,Colland, Frédéric,Maragno, Ana-Leticia,Demarles, Didier,Geneste, Olivier,Kotschy, Andras
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p. 13762 - 13795
(2020/12/02)
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- Rh-Catalyzed Base-Free Decarbonylative Borylation of Twisted Amides
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We report the rhodium-catalyzed base-free decarbonylative borylation of twisted amides. The synthesis of versatile arylboronate esters from aryl twisted amides is achieved via decarbonylative rhodium(I) catalysis and highly selective N-C(O) insertion. The method is notable for a very practical, additive-free Rh(I) catalyst system. The method shows broad functional group tolerance and excellent substrate scope, including site-selective decarbonylative borylation/Heck cross-coupling via divergent N-C/C-Br cleavage and late-stage pharmaceutical borylation.
- Bie, Fusheng,Liu, Xuejing,Shi, Yijun,Cao, Han,Han, Ying,Szostak, Michal,Liu, Chengwei,Liu, Xuejing,Szostak, Michal,Liu, Chengwei
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p. 15676 - 15685
(2020/11/13)
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- Visible-Light-Induced Ni-Catalyzed Radical Borylation of Chloroarenes
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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.
- 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)
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- Redox-Neutral Borylation of Aryl Sulfonium Salts via C-S Activation Enabled by Light
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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.
- Huang, Chen,Feng, Jie,Ma, Rui,Fang, Shuaishuai,Lu, Tao,Tang, Weifang,Du, Ding,Gao, Jian
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p. 9688 - 9692
(2019/12/02)
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- Photocatalyzed borylation using water-soluble quantum dots
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The synthesis of arylboronates by Sandmeyer-type reactions in the presence of water still remains a significant challenge. Herein, we report the use of water-soluble MPA-capped quantum dot (QD) photocatalysts for the borylation of diazonium salts in the presence of water. A biphasic system under mild acidic conditions remains critical to prevent decomposition and competitive disulphide bond formation. The present protocol offers a broader scope of substrates and borylating agents. Additionally, this catalytic system offers a significantly high turnover number (TON). The present methodology can effectively distinguish subtle reactivity differences between boronic acids and boronates. Mechanistic investigation suggests an excited-state electron transfer pathway.
- Chandrashekar, Hediyala B.,Maji, Arun,Halder, Ganga,Banerjee, Sucheta,Bhattacharyya, Sayan,Maiti, Debabrata
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supporting information
p. 6201 - 6204
(2019/06/07)
-
- Cleavage of C(aryl)?CH3 Bonds in the Absence of Directing Groups under Transition Metal Free Conditions
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Organic chemists now can construct carbon–carbon σ-bonds selectively and sequentially, whereas methods for the selective cleavage of carbon–carbon σ-bonds, especially for unreactive hydrocarbons, remain limited. Activation by ring strain, directing groups, or in the presence of a carbonyl or a cyano group is usually required. In this work, by using a sequential strategy site-selective cleavage and borylation of C(aryl)?CH3 bonds has been developed under directing group free and transition metal free conditions. Methyl groups of various arenes are selectively cleaved and replaced by boryl groups. Mechanistic analysis suggests that it proceeds by a sequential intermolecular oxidation and coupling of a transient aryl radical, generated by radical decarboxylation, involving a pyridine-stabilized persistent boryl radical.
- Dai, Peng-Fei,Ning, Xiao-Shan,Wang, Hua,Cui, Xian-Chao,Liu, Jie,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 5392 - 5395
(2019/03/29)
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- Visible-Light-Induced Organocatalytic Borylation of Aryl Chlorides
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The preparation of arylboronates from unactivated aryl chlorides in a transition-metal-free manner is rather challenging. There are only few examples to achieve this goal by using ultraviolet irradiation. Based on the mechanistic understanding of the diboron/methoxide/pyridine reaction system, we achieved photoactivation of the in situ generated super electron donor and developed a visible-light-induced organocatalytic method for efficient borylation of unactivated aryl chlorides.
- Zhang, Li,Jiao, Lei
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p. 9124 - 9128
(2019/06/17)
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- Additive- and Photocatalyst-Free Borylation of Arylazo Sulfones under Visible Light
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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.
- Xu, Yuliang,Yang, Xinying,Fang, Hao
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p. 12831 - 12837
(2018/10/20)
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- Palladium-Catalyzed Decarbonylative Borylation of Carboxylic Acids: Tuning Reaction Selectivity by Computation
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Decarbonylative borylation of carboxylic acids is reported. Carbon electrophiles are generated directly after reagent-enabled decarbonylation of the in situ accessible sterically-hindered acyl derivative of a carboxylic acid under catalyst controlled conditions. The scope and the potential impact of this method are demonstrated in the selective borylation of a variety of aromatics (>50 examples). This strategy was used in the late-stage derivatization of pharmaceuticals and natural products. Computations reveal the mechanistic details of the unprecedented C?O bond activation of carboxylic acids. By circumventing the challenging decarboxylation, this strategy provides a general synthetic platform to access arylpalladium species for a wide array of bond formations from abundant carboxylic acids. The study shows a powerful combination of experiment and computation to predict decarbonylation selectivity.
- Liu, Chengwei,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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supporting information
p. 16721 - 16726
(2018/11/30)
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- METHODS OF MANUFACTURING OF BORON COMPOUND WITHOUT TRANSITION METALS
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The present invention refers to aryl boron compound number bath method relates to search, more particularly transition metal catalyst to a tank without the use of boron compounds number is given to the aryl organic halo [ceyn [ceyn] freight method are disclosed to boron. (by machine translation)
- -
-
Paragraph 0062; 0063; 0071; 0072; 0076
(2018/05/03)
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- Transition-Metal-Free, Visible-Light-Enabled Decarboxylative Borylation of Aryl N-Hydroxyphthalimide Esters
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Herein, we report a conceptually novel borylation reaction proceeding via a mild photoinduced decarboxylation of redox-activated aromatic carboxylic acids. This work constitutes the first application of cheap and easily prepared N-hydroxyphthalimide esters as aryl radical precursors and does not require the use of expensive transition metals or ligands. The reaction is operationally simple, scalable, and displays broad scope and functional group tolerance.
- Candish, Lisa,Teders, Michael,Glorius, Frank
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p. 7440 - 7443
(2017/06/13)
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- Chemoselective coupling of 1,1-bis[(pinacolato)boryl]alkanes for the transition-metal-frec borylation of aryl and vinyl halides: A combined experimental and theoretical investigation
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A new transition-metal-frec borylation of aryl and vinyl halides using l,l-bis[(pinacolato)boryl]alkanes as boron sources is described. In this transformation one of the boron groups from 1,1-bis[(pinacolato)boryl]alkanes is selectively transferred to aryl and vinyl halides in the presence of sodium tert-butoxide as the only activator to form organoboronate esters. Under the developed borylation conditions, a broad range of organohalides are borylated with excellent chemo-selectivity and functional group compatibility, thus offering a rare example of a transition-metal-frec borylation protocol. Experimental and theoretical studies have becn performed to elucidate the reaction mechanism, revealing the unusual formation of Lewis acid/base adduct betwecn organohalides and α-borylcarbanion, generated in situ from the reaction of l,l-bis[(pinacolato)boryl]alkanes with an alkoxide base, to facilitate the borylation reactions.
- Lee, Yeosan,Baek, Seung-Yeol,Park, Jinyoung,Kim, Seoung-Tae,Tussupbayev, Samat,Kim, Jeongho,Baik, Mu-Hyun,Cho, Seung Hwan
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p. 975 - 984
(2017/05/16)
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- Radical Metal-Free Borylation of Aryl Iodides
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A simple metal-free borylation of aryl iodides mediated by a fluoride sp 2 -sp 3 diboron adduct is described. The reaction conditions are compatible with various functional groups. Electronic effects of substituents do not affect the borylation while steric hindrance does. The reaction proceeds via a radical mechanism in which pyridine serves to stabilize the boryl radicals, generated in situ.
- Pinet, Sandra,Liautard, Virginie,Debiais, Mégane,Pucheault, Mathieu
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p. 4759 - 4768
(2017/10/03)
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- Pyridine-catalyzed radical borylation of aryl halides
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A pyridine-catalyzed transition-metal-free borylation reaction of haloarenes has been developed based on the selective cross-coupling of an aryl radical and a pyridine-stabilized boryl radical. Arylboronates were produced from haloarenes under mild conditions. This borylation reaction features a broad substrate scope, operational simplicity, and gram-scale synthetic ability.
- Zhang, Li,Jiao, Lei
-
supporting information
p. 607 - 610
(2017/05/15)
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- Preparation method of aryl borate ester and allyl borate ester
-
The invention discloses a preparation method of aryl borate ester and allyl borate ester. The method comprises the following step: under the catalytic action of pyridine or a derivative thereof, carrying out 1) or 2) to obtain substituted boric acid ester shown as a formula I-1 or a formula I-2: 1) a reaction of a halide, bi-boric acid ester and alkoxide; 2) a reaction of a halide and a bi-boric acid ester-alkoxide complex. The method is an efficient preparation method of the aryl borate ester and the allyl borate ester. In the preparation method provided by the invention, the inexpensive pyridine or the derivative thereof is taken as a catalyst instead of a transition metal catalyst, the reaction conditions are mild, the reaction yield is high, residues of trace transition metal in a boronation product are avoided, and the cost of an aryl and allyl borate ester synthesis reaction is lowered.
- -
-
Paragraph 0073-0074; 0077
(2017/07/12)
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- C-H borylation by platinum catalysis
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Herein, we describe the platinum-catalyzed borylation of aromatic C-H bonds. N-Heterocyclic carbene-ligated platinum catalysts are found to be efficient catalysts for the borylation of aromatic C(sp2)-H bonds when bis(pinacolato)diboron is used as the boron source. The most remarkable feature of these Pt catalysts is their lack of sensitivity towards the degree of steric hindrance around the C-H bonds undergoing the borylation reaction. These Pt catalysts allow for the synthesis of sterically congested 2,6-disubstituted phenylboronic esters, which are otherwise difficult to synthesize using existing C-H borylation methods. Furthermore, platinum catalysis allows for the site-selective borylation of the C-H bonds ortho to fluorine substituents in fluoroarene systems. Preliminary mechanistic studies and work towards the synthetic application of this platinum catalyzed C-H borylation process are described.
- Furukawa, Takayuki,Tobisu, Mamoru,Chatani, Naoto
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p. 332 - 342
(2017/05/09)
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- Visible-Light Photoredox Borylation of Aryl Halides and Subsequent Aerobic Oxidative Hydroxylation
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Efficient and practical visible-light photoredox borylation of aryl halides and subsequent aerobic oxidative hydroxylation were developed. The protocols use readily available aryl halides and bis(pinacolato)diboron as the starting materials, fac-Ir(ppy)3 as the photocatalyst, and corresponding arylboronic esters and phenols were obtained in good yields. The methods show some advantages including simple equipment, mild conditions, easy operation, and wide substrate scope. Therefore, they should provide a valuable strategy for chemical transformations.
- Jiang, Min,Yang, Haijun,Fu, Hua
-
supporting information
p. 5248 - 5251
(2016/11/02)
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- High-Turnover Aromatic C-H Borylation Catalyzed by POCOP-Type Pincer Complexes of Iridium
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The catalytic C-H borylation of arenes with HBpin (pin = pinacolate) using POCOP-type pincer complexes of Ir has been demonstrated, with turnover numbers exceeding 10 000 in some cases. The selectivity of C-H activation was based on steric preferences and largely mirrored that found in other Ir borylation catalysts. Catalysis in the (POCOP)Ir system depends on the presence of stoichiometric quantities of sacrificial olefin, which is hydrogenated to consume the H2 equivalents generated in the borylation of C-H bonds with HBpin. Smaller olefins such as ethylene or 1-hexene were more advantageous to catalysis than sterically encumbered tert-butylethylene (TBE). Olefin hydroboration is a competing side reaction. The synthesis and isolation of multiple complexes potentially relevant to catalysis permitted examination of several key elementary reactions. These experiments indicate that the C-H activation step in catalysis ostensibly involves oxidative addition of an aromatic C-H bond to the three-coordinate (POCOP)Ir species. The olefin is mechanistically critical to gain access to this 14-electron, monovalent Ir intermediate. C-H activation at Ir(I) here is in contrast to the olefin-free catalysis with state-of-the-art Ir complexes supported by neutral bidentate ligands, where the C-H activating step is understood to involve trivalent Ir-boryl intermediates.
- Press, Loren P.,Kosanovich, Alex J.,McCulloch, Billy J.,Ozerov, Oleg V.
-
supporting information
p. 9487 - 9497
(2016/08/12)
-
- Preparation and reactions of 4-iodobutyl pinacolborate. Synthesis of substituted alkyl and aryl pinacolboronates via 4-iodobutyl pinacolborate utilizing tetrahydrofuran as the leaving group
-
Iodine reacts with 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (HBpin), under ambient reaction conditions in THF, to form the iodoalkylborate species 2-(4-iodobutoxy)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (4-IboxBpin). Apparently, one-half equivalent of I2 reacts with HBpin to form IBpin in pentanes, which in turn cleaves THF to form the 4-IboxBpin. Alkyl and aryl Grignard reagents, prepared under Barbier conditions, then react with 4-IboxBpin to form the corresponding alkyl and aryl pinacolboronates while reforming and liberating THF as the leaving group.
- Murphy, Chris L.,Hall, Aaron,Roberts, Emily J.,Ryan, Matthew D.,Clary, Jacob W.,Singaram, Bakthan
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p. 3032 - 3033
(2015/02/19)
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- Fluorine-controlled C-H borylation of arenes catalyzed by a PSiN-pincer platinum complex
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An efficient, regioselective synthesis of fluorine-substituted arylboronic esters was achieved through fluorine-controlled C-H borylation of arenes with diboron catalyzed by a PSiN-platinum complex. The promising utility of the PSiN-platinum catalyst and its unique regioselectivity were demonstrated for the first time, which would complement the well-developed Ir-catalyzed C-H borylation.
- Takaya, Jun,Ito, Shisei,Nomoto, Hironori,Saito, Narumasa,Kirai, Naohiro,Iwasawa, Nobuharu
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supporting information
p. 17662 - 17665
(2015/12/18)
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- C-H Functionalization at Sterically Congested Positions by the Platinum-Catalyzed Borylation of Arenes
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Despite significant progress in the area of C-H bond functionalization of arenes, no general method has been reported for the functionalization of C-H bonds at the sterically encumbered positions of simple arenes, such as mesitylene. Herein, we report the development of the first platinum-based catalyst for C-H borylation of arenes and heteroarenes. Notably, this method exhibited high tolerance toward steric hindrance and provided rapid access to a series of 2,6-disubstituted phenylboronic esters, valuable building blocks for further elaborations.
- Furukawa, Takayuki,Tobisu, Mamoru,Chatani, Naoto
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supporting information
p. 12211 - 12214
(2015/10/12)
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- Silyl phosphorus and nitrogen donor chelates for homogeneous ortho borylation catalysis
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Ir catalysts supported by bidentate silyl ligands that contain P- or N-donors are shown to effect ortho borylations for a range of substituted aromatics. The substrate scope is broad, and the modular ligand synthesis allows for flexible catalyst design.
- Ghaffari, Behnaz,Preshlock, Sean M.,Plattner, Donald L.,Staples, Richard J.,Maligres, Peter E.,Krska, Shane W.,Maleczka, Robert E.,Smith, Milton R.
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supporting information
p. 14345 - 14348
(2014/12/10)
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- Borylation using group IV metallocene under mild conditions
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A borylation reaction of aromatic diazonium salts has been optimized using titanocene and zirconocene derivatives as catalysts. The reaction employs diisopropylaminoborane as a borylating agent and proceeds smoothly at room temperature to provide arylboronates after methanolysis and transesterification with pinacol. The reaction mechanism has been found to proceed via a radical pathway.
- Marciasini, Ludovic D.,Vaultier, Michel,Pucheault, Mathieu
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p. 1702 - 1705
(2014/03/21)
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- NEW PROCESS FOR PREPARING ARYLBORANES BY ARYLATION OF ORGANOBORON COMPOUNDS
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The present invention relates to a new process for the preparation of an arylborane compound, by arylation of a B-H bond, which comprises a step (1) of contacting an arenediazonium salt or a heteroarenediazonium salt with an organoboron compound containing at least one B-H bond, in a reaction medium containing a solvent, in the absence of base, in the absence or in the presence of an activating agent, for the preparation of an arylborane compound, and a possible step (2) of recovery and purification of said arylborane compound obtained at the step (1), said arylborane being in particular an aminoarylborane, and a possible step (3) of refunctionalisation of said arylborane obtained at step (1) or (2) for the preparation of aryl boronic derivatives or arylborates.
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Page/Page column 53-54; 67-68
(2014/02/15)
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- B-H bond cleavage via metal-ligand cooperation by dearomatized ruthenium pincer complexes
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Organic derivatives of boronic acid are widely used reagents useful in various synthetic applications. A fundamental understanding and the exploration of new reaction pathways of boronic reagents with organometallic systems hold promise for useful advancement in chemical catalysis. Herein we present the reactions of simple boranes with dearomatized ruthenium pincer complexes based on PNP (2,6-bis(di-tert-butylphosphinomethyl)pyridine) or PNN (2-(di-tert-butylphosphinomethyl)-6-(diethylaminomethyl)pyridine) ligands. NMR studies revealed dehydrogenative addition of the borane B-H bond across the metal center and the ligand. Remarkably, new complexes were observed, which contain the boryl moiety at the benzylic carbon of the pincer ligand arm. X-ray crystal structures of new dearomatized boryl pincer complexes were obtained, and DFT calculations revealed mechanistic details of the adduct formation process through a dehydrogenative pathway. In addition, catalytic aryl-boron coupling reactions were explored. The new boryl pincer systems may possibly be useful in future postmodification techniques for ruthenium pincer complexes, as well as in catalytic B-B and B-C coupling reactions.
- Anaby, Aviel,Butschke, Burkhard,Ben-David, Yehoshoa,Shimon, Linda J. W.,Leitus, Gregory,Feller, Moran,Milstein, David
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supporting information
p. 3716 - 3726
(2014/08/18)
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- New process for preparing arylboranes by arylation of organoboron compounds
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The present invention relates to a new process for the preparation of an arylborane compound, by arylation of a B-H bond, which comprises a step (1) of contacting an arenediazonium salt or a heteroarenediazonium salt with an organoboron compound containing at least one B-H bond, in a reaction medium containing a solvent, in the absence of base, in the absence or in the presence of an activating agent, for the preparation of an arylborane compound, and a possible step (2) of recovery and purification of said arylborane compound obtained at the step (1), said arylborane being in particular an aminoarylborane, and a possible step (3) of refunctionalisation of said arylborane obtained at step (1) or (2) for the preparation of aryl boronic derivatives or arylborates.
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-
Paragraph 0108; 0109; 0110; 0111; 0145; 0146
(2014/01/23)
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- Methanol-promoted borylation of arylamines: A simple and green synthetic method to arylboronic acids and arylboronates
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A Sandmeyer borylation of arylamines via a SN2Ar pathway promoted by methanol with sodium nitrite and hydrochloric acid as diazotization agent has been developed, which provide a simple and green synthetic method to arylboronic acids and arylboronates. Georg Thieme Verlag Stuttgart New York.
- Zhao, Cong-Jun,Xue, Dong,Jia, Zhi-Hui,Wang, Chao,Xiao, Jianliang
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supporting information
p. 1577 - 1584
(2014/07/08)
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- Design, generation, and synthetic application of borylzincate: Borylation of aryl halides and borylzincation of benzynes/terminal alkyne
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Borylzincate was generated in situ from dialkylzinc, diboron, and metal alkoxide. Model DFT calculations showed that although the formation of borylzincate is kinetically favorable, it is thermodynamically unfavorable. Therefore, we designed a successive reaction sequence that would provide a compensating energy gain. This enabled Zn-catalyzed borylation of aryl halides and borylzincation of benzynes and terminal alkyne from diborons without the need for any cocatalyst.
- Nagashima, Yuki,Takita, Ryo,Yoshida, Kengo,Hirano, Keiichi,Uchiyama, Masanobu
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supporting information
p. 18730 - 18733
(2014/01/06)
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- Iron-catalysed borylation of arenediazonium salts to give access to arylboron derivatives via aryl(amino)boranes at room temperature
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Complementary to previously described Miyaura borylation methods, a new access to boron derivatives via aryl(amino)boranes is described. Direct coupling between aryldiazonium salts and diisopropylaminoborane is catalysed by 0.1% ferrocene leading to the formation of a carbon-boron bond. The obtained aryl(amino)boranes could eventually then be transformed into boronic acids, boronates or borates. Copyright
- Marciasini, Ludovic D.,Richy, Nicolas,Vaultier, Michel,Pucheault, Mathieu
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supporting information
p. 1083 - 1088
(2013/05/21)
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- Intermolecular C-H bond activation of alkanes and arenes by NCN pincer iridium(III) acetate complexes containing bis(oxazolinyl)phenyl ligands
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Carbon-hydrogen bond activation of arenes by the pincer Ir(III) acetate complex (phebox)Ir(OAc)2(H2O) (1; phebox = bis(oxazolinyl)phenyl) proceeded at 100 °C to give the corresponding aryl Ir(III) complexes (phebox)Ir(Ar)(OAc) in high yields. Reactions of the monosubstituted arenes anisole, toluene, chlorobenzene, acetophenone, and nitrobenzene resulted in the formation of meta- and para-substituted aryl complexes in high yields. Competitive experiments between two monosubstituted arenes exhibited relative reaction rates in the order C6H 5OMe > C6H5NO2 > C 6H5COMe > C6H5Cl > C 6H5Me. The kinetic isotope effects of C-H bond activation of benzene and nitrobenzene were determined to be 2.9 ± 0.1 and 2.0 ± 0.4, respectively. The Ir complex 1 underwent catalytic borylation of arenes with bis(pinacolato)diboron (B2(pin)2) or pinacolborane (HB(pin)), giving the corresponding borylated products. The Ir complex 1 was also reactive toward alkane C-H bond activation, demonstrated by the reactions with n-heptane and n-octane at 160 °C that cleanly afforded the corresponding alkyl complexes (phebox)Ir(n-CnH 2n+1)(OAc) (n = 7, 8, respectively).
- Ito, Jun-Ichi,Kaneda, Tomoko,Nishiyama, Hisao
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experimental part
p. 4442 - 4449
(2012/08/27)
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- Rhodium-catalyzed cross-coupling reaction of arylboronates and diazoesters and tandem alkylation reaction for the synthesis of quaternary r,r-heterodiaryl carboxylic esters
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A rhodium-catalyzed one-pot three-component coupling reaction was developed for the synthesis of quaternary α,α-heterodiaryl carboxylic esters. This reaction involves cross-coupling of the arylrhodium(I) complexes with R-aryldiazoacetates to form oxa-π-al
- Tsoi, Yuk-Tai,Zhou, Zhongyuan,Yu, Wing-Yiu
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supporting information; experimental part
p. 5370 - 5373
(2011/12/03)
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- Unsaturated iridium pyridinedicarboxylate pincer complexes with catalytic activity in borylation of arenes
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Unsaturated σ,π-cyclooctenyl and hydrido Ir(iii) complexes bearing an unusual tridentate dianionic ONO pincer-type ligand have been straightforwardly obtained from 2,6-pyridinedicarboxylic acid and standard Ir(i) starting materials. These complexes efficiently catalyzed the arene C-H borylation under thermal conditions. The Royal Society of Chemistry 2011.
- Hanh Nguyen, Duc,Perez-Torrente, Jesus J.,Lomba, Laura,Victoria Jimenez,Lahoz, Fernando J.,Oro, Luis A.
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p. 8429 - 8435
(2011/10/10)
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- A new enabling technology for convenient laboratory scale continuous flow processing at low temperatures
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A new machine for conducting continuous flow processes at low temperatures on a laboratory scale is reported. The use of this cryogenic flow reactor has been demonstrated by the preparation of a variety of (hetero)aromatic boronic acids and esters via lit
- Browne, Duncan L.,Baumann, Marcus,Harji, Bashir H.,Baxendale, Ian R.,Ley, Steven V.
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supporting information; experimental part
p. 3312 - 3315
(2011/09/12)
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- METHOD FOR PREPARING AN AROMATIC BORON REAGENT THROUGH BARBIER-TYPE REACTION
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The present invention discloses a method for preparing an aromatic boron reagent through Barbier-type reaction, comprising reacting an aromatic halogen compound with a boron compound in the presence of a metal to obtain an aromatic boron reagent, wherein the metal may be or may not be activated by an activator. The method according to the present invention can avoid using expensive and complicated procedures of prior art and hence is efficient and economic.
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Page/Page column 6
(2010/12/29)
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- 2-Amino-aryl-7-aryl-benzoxazoles as potent, selective and orally available JAK2 inhibitors
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A series of novel benzoxazole derivatives has been designed and shown to exhibit attractive JAK2 inhibitory profiles in biochemical and cellular assays, capable of delivering compounds with favorable PK properties in rats. Synthesis and structure-activity relationship data are also provided.
- Gerspacher, Marc,Furet, Pascal,Pissot-Soldermann, Carole,Gaul, Christoph,Holzer, Philipp,Vangrevelinghe, Eric,Lang, Marc,Erdmann, Dirk,Radimerski, Thomas,Regnier, Catherine H.,Chene, Patrick,Pover, Alain De,Hofmann, Francesco,Baffert, Fabienne,Buhl, Thomas,Aichholz, Reiner,Blasco, Francesca,Endres, Ralf,Trappe, J?rg,Drueckes, Peter
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scheme or table
p. 1724 - 1727
(2010/07/03)
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- Direct conversion of arylamines to pinacol boronates: A metal-free borylation process
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Leave the metal out: Arylboronates are produced In moderate to good yields by direct borylation of readily available aryl amines (see scheme). The reaction can be carried out under air at room temperature and transition-metal catalysis is not required. The boronate products can be used without purification in SuzukiMiyaura cross-coupling reactions. Chemical equation representation
- Mo, Fanyang,Jiang, Yubo,Qiu, Di,Zhang, Yan,Wang, Jianbo
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supporting information; experimental part
p. 1846 - 1849
(2010/06/16)
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- Gold(iii)-catalyzed halogenation of aromatic boronates with N -halosuccinimides
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Aromatic boronates bearing halogen substituents in the aromatic ring can be synthesized by AuCl3-catalyzed halogenations with N-halosuccinimides.
- Qiu, Di,Mo, Fanyang,Zheng, Zhitong,Zhang, Yan,Wang, Jianbo
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supporting information; experimental part
p. 5474 - 5477
(2011/02/22)
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- Iridium complexes of N-heterocyclic carbenes in C-H borylation using energy efficient microwave technology: Influence of structure, ligand donor strength and counter ion on catalytic activity
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Bridged and unbridged N-heterocyclic carbene (NHC) ligands were metalated with [Ir(COD)Cl]2 to give iridium(i) mono- and biscarbene substituted catalysts [Ir(COD)NHC(Cl)] and [Ir(COD)(NHC)2][X] (X: I, PF 6, BF4, CF3COO, OTf). The prepared NHC-complexes were tested in the C-H borylation reaction of aromatic carbons with bis(pinacolato)diboron (B2pin2) and pinacolborane (HBpin). The use of microwave technology in this study not only facilitates a time efficient screening of a wide range of influences such as ligand σ-donor strength and structural motif as well as the effects of the complex counter ion, but also provides an energy efficient heating source. Catalyst 6TFA, which features a chelating NHC ligand, proved to be most effective catalyst and further investigations with this complex in the borylation of mono- and disubstituted benzene derivatives exploring chemo- and regioselectivity were undertaken. The Royal Society of Chemistry 2009.
- Rentzsch, Christoph F.,Tosh, Evangeline,Herrmann, Wolfgang A.,Kuehn, Fritz E.
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scheme or table
p. 1610 - 1617
(2010/05/18)
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- Iridium-catalyzed preparation of silylboranes by silane borylation and their use in the catalytic borylation of arenes
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Silylboranes are versatile reagents for transition metal-catalyzed reactions of unsaturated organic molecules. These reagents are typically prepared by the addition of a silyl lithium species to a boron electrophile. However, the need to generate anionic silane reagents limits the scope of silylboranes that can be readily obtained. Here, we describe the synthesis of trialkylsilylboranes by the borylation of silanes catalyzed by iridium complexes. The reaction of trialkylhydrosilanes with B2pin 2 catalyzed by the combination of [Ir(OMe)cod]2 and 4,4′-di-tert-butylbipyridine forms trialkylsilylboronic esters. In addition, we show that these trialkylsilylboranes serve as boron sources for the iridium-catalyzed borylation of aryl C-H bonds. In contrast to diboron reagents, the silylboranes react with methylarenes at both the aryl and methyl C-H bonds.
- Boebel, Timothy A.,Hartwig, John F.
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p. 6013 - 6019
(2009/04/13)
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