- Cu-mediated: vs. Cu-free selective borylation of aryl alkyl sulfones
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A Cu-catalysed borylation of aryl alkyl sulfones was developed for the high yield synthesis of versatile arylboronic esters using a readily prepared NHC-Cu catalyst. In addition, the selective cleavage of either alkyl(C)-sulfonyl or aryl(C)-sulfonyl bonds
- Hu, Jiefeng,Huang, Mingming,Marder, Todd B.,Radius, Udo,Tang, Man,Westcott, Stephen A.
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supporting information
p. 395 - 398
(2022/01/19)
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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)
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- Unreactive C-N Bond Activation of Anilines via Photoinduced Aerobic Borylation
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Unreactive C-N bond activation of anilines was achieved by photoinduced aerobic borylation. A diverse range of tertiary and secondary anilines were converted to aryl boronate esters in moderate to good yields with wide functional group tolerance under simple and ambient photochemical conditions. This transformation achieved the direct and facile C-N bond activation of unreactive anilines, providing a convenient and practical route transforming widely available anilines into useful aryl boronate esters.
- Ji, Shuohan,Qin, Shengxiang,Yin, Chunyu,Luo, Lu,Zhang, Hua
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supporting information
p. 64 - 68
(2021/12/27)
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- Palladium-catalyzed borylation of aryl bromides and chlorides using phosphatrioxa-adamantane ligands
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Catalysts based on the combination of Pd(OAc)2 and the electron-deficient phosphatrioxa-adamantane ligands are described for borylation of aryl bromides and chlorides. Catalytic evaluation of a small library of phosphatrioxa-adamantane ligands provided some insights on the preferred ligand steric profile for borylation reactions. The corresponding aryl boronate esters were accessed under mild conditions (25–70 °C) and isolated in high yields (up to 96%).
- Lamola, Jairus L.,Moshapo, Paseka T.,Holzapfel, Cedric W.,Christopher Maumela, Munaka
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supporting information
(2021/12/13)
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- Organic compound, and organic electroluminescent device and electronic device using same
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The invention relates to an organic compound. The structure of the organic compound comprises a formula I. When the organic compound provided by the invention is used for a light-emitting layer of anorganic electroluminescent device, the device efficiency of the device can be effectively improved, and the service life of the organic electroluminescent device is prolonged.
- -
-
Paragraph 0178-0183
(2021/02/20)
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- Carbon-carbon bond activation by B(OMe)3/B2pin2-mediated fragmentation borylation
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Selective carbon-carbon bond activation is important in chemical industry and fundamental organic synthesis, but remains challenging. In this study, non-polar unstrained Csp2-Csp3 and Csp2-Csp2 bond activation was achieved by B(OMe)3/B2pin2-mediated fragmentation borylation. Various indole derivatives underwent C2-regioselective C-C bond activation to afford two C-B bonds under transition-metal-free conditions. Preliminary mechanistic investigations suggested that C-B bond formation and C-C bond cleavage probably occurred in a concerted process. This new reaction mode will stimulate the development of reactions based on inert C-C bond activation. This journal is
- Chen, Quan,Jiang, Jiachen,Wang, Li,Wu, Aizhen,Yin, Youzhi,Zhang, Hua,Zhang, Ke,Zhao, Mengzhen,Zhong, Qi,Zou, Youliang
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p. 15104 - 15109
(2021/12/09)
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- Synthesis of arylboronates via the Pd-catalyzed desulfitative coupling reaction of sodium arylsulfinates with bis(pinacolato)diboron
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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
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- Photo-induced thiolate catalytic activation of inert Caryl-hetero bonds for radical borylation
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Substantial effort is currently being devoted to obtaining photoredox catalysts with high redox power. Yet, it remains challenging to apply the currently established methods to the activation of bonds with high bond dissociation energy and to substrates with high reduction potentials. Herein, we introduce a novel photocatalytic strategy for the activation of inert substituted arenes for aryl borylation by using thiolate as a catalyst. This catalytic system exhibits strong reducing ability and engages non-activated Caryl–F, Caryl–X, Caryl–O, Caryl–N, and Caryl–S bonds in productive radical borylation reactions, thus expanding the available aryl radical precursor scope. Despite its high reducing power, the method has a broad substrate scope and good functional-group tolerance. Spectroscopic investigations and control experiments suggest the formation of a charge-transfer complex as the key step to activate the substrates.
- K?nig, Burkhard,Wang, Hua,Wang, Shun
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supporting information
p. 1653 - 1665
(2021/06/17)
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- Catalytic Boration of Alkyl Halides with Borane without Hydrodehalogenation Enabled by Titanium Catalyst
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An unprecedented and general titanium-catalyzed boration of alkyl (pseudo)halides (alkyl-X, X=I, Br, Cl, OMs) with borane (HBpin, HBcat) is reported. The use of titanium catalyst can successfully suppress the undesired hydrodehalogenation products that prevail using other transition-metal catalysts. A series of synthetically useful alkyl boronate esters are readily obtained from various (primary, secondary, and tertiary) alkyl electrophiles, including unactivated alkyl chlorides, with tolerance of other reducing functional groups such as ester, alkene, and carbamate. Preliminary studies on the mechanism revealed a possible radical reaction pathway. Further extension of our strategy to aryl bromides is also demonstrated.
- Wang, Xianjin,Cui, Penglei,Xia, Chungu,Wu, Lipeng
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supporting information
p. 12298 - 12303
(2021/05/07)
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- Improvement in the Palladium-Catalyzed Miyaura Borylation Reaction by Optimization of the Base: Scope and Mechanistic Study
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Aryl boronic acids and esters are important building blocks in API synthesis. The palladium-catalyzed Suzuki-Miyaura borylation is the most common method for their preparation. This paper describes an improvement of the current reaction conditions. By using lipophilic bases such as potassium 2-ethyl hexanoate, the borylation reaction could be achieved at 35 °C in less than 2 h with very low palladium loading (0.5 mol %). A preliminary mechanistic study shows a hitherto unrecognized inhibitory effect by the carboxylate anion on the catalytic cycle, whereas 2-ethyl hexanoate minimizes this inhibitory effect. This improved methodology enables borylation of a wide range of substrates under mild conditions.
- Barroso, Santiago,Joksch, Markus,Puylaert, Pim,Tin, Sergey,Bell, Stephen J.,Donnellan, Luke,Duguid, Stewart,Muir, Colin,Zhao, Peichao,Farina, Vittorio,Tran, Duc N.,De Vries, Johannes G.
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supporting information
p. 103 - 109
(2020/12/22)
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- Light- and Manganese-Initiated Borylation of Aryl Diazonium Salts: Mechanistic Insight on the Ultrafast Time-Scale Revealed by Time-Resolved Spectroscopic Analysis
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Manganese-mediated borylation of aryl/heteroaryl diazonium salts emerges as a general and versatile synthetic methodology for the synthesis of the corresponding boronate esters. The reaction proved an ideal testing ground for delineating the Mn species responsible for the photochemical reaction processes, that is, involving either Mn radical or Mn cationic species, which is dependent on the presence of a suitably strong oxidant. Our findings are important for a plethora of processes employing Mn-containing carbonyl species as initiators and/or catalysts, which have considerable potential in synthetic applications.
- Firth, James D.,Hammarback, L. Anders,Burden, Thomas J.,Eastwood, Jonathan B.,Donald, James R.,Horbaczewskyj, Chris S.,McRobie, Matthew T.,Tramaseur, Adam,Clark, Ian P.,Towrie, Michael,Robinson, Alan,Krieger, Jean-Philippe,Lynam, Jason M.,Fairlamb, Ian J. S.
-
supporting information
p. 3979 - 3985
(2021/02/03)
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- Unveiling Extreme Photoreduction Potentials of Donor-Acceptor Cyanoarenes to Access Aryl Radicals from Aryl Chlorides
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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.
- Cao, Jilei,Tang, Xinxin,Toh, Ren Wei,Wang, Han,Wu, Jie,Wu, Xiangyang,Xu, Jinhui,Yang, Xiaona,Yeow, Edwin K. L.,Zhou, Rong
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supporting information
p. 13266 - 13273
(2021/09/07)
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- Evaluation of the role of graphene-based Cu(i) catalysts in borylation reactions
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Carbon-supported catalysts have been considered as macromolecular ligands which modulate the activity of the metallic catalytic center. Understanding the properties and the factors that control the interactions between the metal and support allows a fine tuning of the catalyzed processes. Although huge effort has been devoted to comprehending binding energies and charge transfer for single atom noble metals, the interaction of graphenic surfaces with cheap and versatile Cu(i) salts has been scarcely studied. A methodical experimental and theoretical analysis of different carbon-based Cu(i) materials in the context of the development of an efficient, general, scalable, and sustainable borylation reaction of aliphatic and aromatic halides has been performed. We have also examined the effect of microwave (MW) radiation in the preparation of these type of materials using sustainable graphite nanoplatelets (GNP) as a support. A detailed analysis of all the possible species in solution revealed that the catalysis is mainly due to an interesting synergetic Cu2O/graphene performance, which has been corroborated by an extensive theoretical study. We demonstrated through DFT calculations at a high level of theory that graphene enhances the reactivity of the metal in Cu2O against the halide derivative favoring a radical departure from the halogen. Moreover, this material is able to stabilize radical intermediates providing unexpected pathways not observed using homogeneous Cu(i) catalysed reactions. Finally, we proved that other common carbon-based supports like carbon black, graphene oxide and reduced graphene oxide provided poorer results in the borylation process.
- Cid, M. B.,Díaz, Cristina,Franco, Mario,Lamsabhi, Al Mokhtar,Sainz, Raquel,Tortosa, Mariola
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p. 3501 - 3513
(2021/06/06)
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- 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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- Cross-Coupling through Ag(I)/Ag(III) Redox Manifold
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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.
- Demonti, Luca,Mézailles, Nicolas,Nebra, Noel,Saffon-Merceron, Nathalie
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supporting information
p. 15396 - 15405
(2021/10/12)
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- Decarboxylative Borylation of Stabilized and Activated Carbon Radicals
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Redox-active esters (RAEs) as active radical precursors have been extensively studied for C?B bond formations. However, the analogous transformations of stabilized radicals from the corresponding acid precursors remain challenging owing to the strong preference towards single-electron oxidation to the stable carbocations. This work describes a general strategy for rapid access to various aliphatic and aromatic boronic esters by mild photoinduced decarboxylative borylation. Both aryl and alkyl radicals could be generated from the leaving group-assisted N-hydroxybenzimidoyl chloride esters, even α-CF3 substituted substrates could be activated for further elaboration.
- Li, Xiaojuan,Ni, Shengyang,Pan, Yi,Wang, Yi,Zhang, Qiang,Zhang, Weigang
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supporting information
p. 21875 - 21879
(2020/10/02)
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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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- Hydride Transfer Enables the Nickel-Catalyzed ipso-Borylation and Silylation of Aldehydes
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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.
- Srimontree, Watchara,Guo, Lin,Rueping, Magnus
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supporting information
p. 423 - 427
(2019/12/27)
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- Para-selective borylation of monosubstituted benzenes using a transient mediator
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Herein, we conceptualized a transient mediator approach that has the capability of para-selective C-H functionalization of monosubstituted aromatics. This approach is enabled by in situ generation of a versatile sulfonium salt via highly electrophilic phenoxathiine or thianthrene dication intermediate which can be readily generated from its sulfoxide with trifluoromethanesulfonic anhydride. Preliminary mechanistic study implied that the remarkable para selectivity might be related to the incredible electrophilicity of thianthrene dication intermediate. The versatility of this approach was demonstrated via para-borylation of various monosubstituted simple aromatics combining the sulfonium salt formation with further photocatalyzed transformation.
- Wu, Jie,Wang, Zengwei,Chen, Xiao-Yue,Wu, Yichen,Wang, Daoming,Peng, Qian,Wang, Peng
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p. 336 - 340
(2019/12/09)
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- Pd-Catalyzed Site-Selective Borylation of Simple Arenes via Thianthrenation?
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Site-selective borylation of simple arenes was realized in one pot via an electrophilic thianthrenation/Pd-catalyzed borylation sequence. The key to achieve this operatically simple process is the use of Pd catalysis, which could tolerate the solvent and acidic conditions used in the thianthrenation step. This protocol features mild conditions, broad functional group tolerance, and simple manipulations, and is suitable for late-stage functionalization of a wide range of pharmaceuticals and complex bioactive molecules.
- Chen, Xiao-Yue,Huang, Yu-Hao,Zhou, Jian,Wang, Peng
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supporting information
p. 1269 - 1272
(2020/08/13)
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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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- Reductive Electrophotocatalysis: Merging Electricity and Light to Achieve Extreme Reduction Potentials
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We describe a new electrophotocatalytic strategy that harnesses the power of light and electricity to generate an excited radical anion with a reducing potential of -3.2 V vs SCE, which can be used to activate substrates with very high reduction potentials (Ered ≈ -1.9 to -2.9 V). The resultant aryl radicals can be engaged in various synthetically useful transformations to furnish arylboronate, arylstannane, and biaryl products.
- Kim, Hyunwoo,Kim, Hyungjun,Lambert, Tristan H.,Lin, Song
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supporting information
p. 2087 - 2092
(2020/02/04)
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- Chemoselective Rhodium-Catalyzed Borylation of Bromoiodoarenes under Mild Conditions
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A chemoselective rhodium-catalyzed borylation has been developed for the preparation of aryl boronate esters. The reaction proceeds under mild conditions with excellent selectivity for C-I bonds in bromoiodoarenes and exhibits broad functional group tolerance. This procedure can act as a complementary approach toward bifunctional arenes along with other metal-catalyzed borylations. Additionally, the reaction's utility in the preparation of monomers for metal-catalyzed cross-coupling polymerization is demonstrated.
- Varni, Anthony J.,Bautista, Michael V.,Noonan, Kevin J.T.
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p. 6770 - 6777
(2020/07/21)
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- Preparation method of intermediate
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The invention discloses a preparation method for a Canagliflozin intermediate. The preparation method comprises the steps that substituted bromobenzene as a starting material is reacted with bisdiboron to prepare a boride, and then the Canagliflozin intermediate is prepared through a Suzuki coupling reaction, a Friedel-Crafts acylation reaction and a reduction reaction. The preparation method hasthe advantages that the intermediate product CZ-2 is prepared through the Suzuki coupling reaction, the conditions are mild and easy to operate and control, and the product yield and the product purity are high; aryl methyl is introduced through the Friedel-Crafts acylation reaction, a main chain is built, by means of the route, the yield is high, technological conditions are easy to control, andthe preparation method is suitable for large-scale industrial production.
- -
-
Paragraph 0025-0026
(2020/06/29)
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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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- Photocatalytic C–X borylation of aryl halides by hierarchical SiC nanowire-supported Pd nanoparticles
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Hierarchical SiC nanowire-supported Pd nanoparticles showed high photocatalytic activity for the C-X (X = Br, I) borylation of aryl halides at 30 °C. The SiC/Pd Mott-Schottky contact enhances the rapid transfer of the photogenerated electrons from SiC to the Pd nanoparticles. As a result, the concentrated energetic electrons in the Pd nanoparticles can facilitate the cleavage of C-I or C-Br bonds, which normally requires high-temperature thermal processes. We show that the present Pd/SiC photocatalyst is capable of catalyzing the transformation of a large variety of aryl halides to their corresponding boronate esters under visible light irradiation, with excellent yields.
- Jiao, Zhi-Feng,Zhao, Ji-Xiao,Guo, Xiao-Ning,Guo, Xiang-Yun
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p. 357 - 363
(2019/12/28)
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- Visible-light-mediated borylation of aryl and alkyl halides with a palladium complex
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Palladium catalyzed visible-light-mediated borylation of inactivated aryl and alkyl halides is reported; the method provided high yields and excellent functional group compatibility. Furthermore, arylsilicates were synthesized selectively using dimethylphenylsilyl boronic ester via changing the reaction conditions. Finally, the possible reaction mechanism is determined through fluorescence quenching and turn on/off experiments.
- Zhao, Jia-Hui,Zhou, Zhao-Zhao,Zhang, Yue,Su, Xuan,Chen, Xi-Meng,Liang, Yong-Min
-
supporting information
p. 4390 - 4394
(2020/10/20)
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- Facile and economical Miyaura borylation and one-pot Suzuki–Miyaura cross-coupling reaction
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Facile and economical method for Miyaura borylation reaction between B2pin2 and aryl bromides is reported. The catalytic system containing 2 mol% PdCl2(PPh3)2 and KOAc serves to enable borylations to occur under solvent-free and atmospheric conditions. The developed protocol can be applied to synthesize symmetrical and unsymmetrical biaryls via one-pot two-step Suzuki–Miyaura cross-coupling reaction and also offers the up-scalability.
- Boontiem, Phongsakorn,Kiatisevi, Supavadee
-
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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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- Oxidative Addition of Alkenyl and Alkynyl Iodides to a AuI Complex
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The first isolated examples of intermolecular oxidative addition of alkenyl and alkynyl iodides to AuI are reported. Using a 5,5′-difluoro-2,2′-bipyridyl ligated complex, oxidative addition of geometrically defined alkenyl iodides occurs readily, reversibly and stereospecifically to give alkenyl-AuIII complexes. Conversely, reversible alkynyl iodide oxidative addition generates bimetallic complexes containing both AuIII and AuI centers. Stoichiometric studies show that both new initiation modes can form the basis for the development of C?C bond forming cross-couplings.
- Bower, John F.,Cadge, Jamie A.,Russell, Christopher A.,Sparkes, Hazel A.
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supporting information
p. 6617 - 6621
(2020/03/13)
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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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supporting information
p. 9688 - 9692
(2019/12/02)
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- 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-promoted formation of C-B and C-S bonds under metal- A nd photocatalyst-free conditions
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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.
- Blank, Lena,Fagnoni, Maurizio,Protti, Stefano,Rueping, Magnus
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p. 1243 - 1252
(2019/02/26)
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- Redox reactions of small organic molecules using ball milling and piezoelectric materials
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Over the past decade, photoredox catalysis has harnessed light energy to accelerate bond-forming reactions. We postulated that a complementary method for the redox-activation of small organic molecules in response to applied mechanical energy could be dev
- Kubota, Koji,Pang, Yadong,Miura, Akira,Ito, Hajime
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p. 1500 - 1504
(2020/01/08)
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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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supporting information
p. 9124 - 9128
(2019/06/17)
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- Copper-catalysed borylation of aryl chlorides
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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.
- Kuehn, Laura,Huang, Mingming,Radius, Udo,Marder, Todd B.
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supporting information
p. 6601 - 6606
(2019/07/16)
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- Stoichiometric and Catalytic Aryl?Cl Activation and Borylation using NHC-stabilized Nickel(0) Complexes
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NHC-nickel (NHC=N-heterocyclic carbene) complexes are efficient catalysts for the C?Cl bond borylation of aryl chlorides using NaOAc as a base and B2pin2 (pin=pinacolato) as the boron source. The catalysts [Ni2(ICy)4(μ-(η2:η2)-COD)] (1, ICy=1,3-dicyclohexylimidazolin-2-ylidene; COD=1,5-cyclooctadiene), [Ni(ICy)2(η2-C2H4)] (2), and [Ni(ICy)2(η2-COE)] (3, COE=cyclooctene) compare well with other nickel catalysts reported previously for aryl-chloride borylation with the advantage that no further ligands had to be added to the reaction. Borylation also proceeded with B2neop2 (neop=neopentylglycolato) as the boron source. Stoichiometric oxidative addition of different aryl chlorides to complex 1 was highly selective affording trans-[Ni(ICy)2(Cl)(Ar)] (Ar=4-(F3C)C6H4, 11; 4-(MeO)C6H4, 12; C6H5, 13; 3,5-F2C6H3, 14).
- Kuehn, Laura,Jammal, Dominik G.,Lubitz, Katharina,Marder, Todd B.,Radius, Udo
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supporting information
p. 9514 - 9521
(2019/04/26)
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- Competing dehalogenation versus borylation of aryl iodides and bromides under transition-metal-free basic conditions
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In this work, selectivity-controllable base-promoted transition-metal-free borylation and dehalogenation of aryl halides are described. Under the conditions of borylation, the dehalogenation which emerges as a competitive side reaction has been well-controlled by carefully controlling the borylation conditions. On the other hand, the dehalogenation using benzaldehyde as a hydrogen source has also been accomplished. The applications of direct radical borylation and dehalogenation of aryl halides demonstrate their synthetic practicability in pharmaceutical-oriented organic synthesis. Based on the experimental evidences, the tBuOK/1,10-Phen-triggered radical nature of both competitive reactions has been revealed.
- Niu, Yi-Jie,Sui, Guo-Hui,Zheng, Hong-Xing,Shan, Xiang-Huan,Tie, Lin,Fu, Jia-Le,Qu, Jian-Ping,Kang, Yan-Biao
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p. 10805 - 10813
(2019/09/30)
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- Copper-Photocatalyzed Borylation of Organic Halides under Batch and Continuous-Flow Conditions
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The copper-photocatalyzed borylation of aryl, heteroaryl, vinyl and alkyl halides (I and Br) was reported. The reaction proceeded using a new heteroleptic Cu complex under irradiation with blue LEDs, giving the corresponding boronic-acid esters in good to excellent yields. The reaction was extended to continuous-flow conditions to allow an easy scale-up. The mechanism of the reaction was studied and a mechanism based on a reductive quenching (CuI/CuI*/Cu0) was suggested.
- Nitelet, Antoine,Thevenet, Damien,Schiavi, Bruno,Hardouin, Christophe,Fournier, Jean,Tamion, Rodolphe,Pannecoucke, Xavier,Jubault, Philippe,Poisson, Thomas
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supporting information
p. 3262 - 3266
(2019/02/13)
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- Organophotocatalytic Arene Functionalization: C-C and C-B Bond Formation
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Organophotocatalytic C-C and C-B bond formation reactions of aryl halides have been developed in the presence of an organophotosensitizer, 3,7-di([1,1′-biphenyl]-4-yl)-10-(4-(trifluoromethyl)phenyl)-10H-phenoxazine that has highly negative reduction potential at its photoexcited state. The developed reaction conditions are mild and allow the intermolecular C-C bond formation of the generated aryl radical with electron-rich (hetero)arenes and C-B bond formation with bis(pinacolato)diboron.
- Lee, Da Seul,Kim, Chung Soo,Iqbal, Naila,Park, Gyeong Su,Son, Kyung-Sun,Cho, Eun Jin
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supporting information
p. 9950 - 9953
(2019/12/24)
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- Pd(II) Complexes with Chelating Phosphinoferrocene Diaminocarbene Ligands: Synthesis, Characterization, and Catalytic Use in Pd-Catalyzed Borylation of Aryl Bromides
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We developed a novel, straightforward route toward Pd(II)-aminocarbene complexes bearing a P-chelating phosphinoferrocenyl substituent based on a three-component reaction of 1′-(diphenylphosphino)-1-isocyanoferrocene (1) with [PdCl2(cod)] (cod = cycloocta-1,5-diene) and nucleophilic amines. Depending on the type of the amine, the reaction produced acyclic diaminocarbenes and their saturated (imidazolin-2-ylidene) and unsaturated (imidazol-2-ylidene) cyclic counterparts (NHCs). Using (S)-2-(chloromethyl)pyrrolidine as the nucleophile, this method afforded a separable pair of stable diastereomeric bicyclic imidazolin-2-ylidene carbenes with different configurations of the planar-chiral ferrocene unit. The prepared P-chelating carbenes were characterized using spectroscopic methods, X-ray crystallography, and DFT methods. The last were used to explain the formation of isomeric open diaminocarbenes featuring NHR groups at the wing-tip position, trends in Pd-Cl bond lengths reflecting similar trans influences of the particular carbene and phosphine donors, and the results from cyclic voltammetric measurements. Furthermore, the carbenes were used as defined (pre)catalysts in Miyaura borylation of aryl bromides with bis(pinacolato)diboron. When applying the optimized catalytic system (1 mol % Pd catalyst, KOAc as the base, 2-propanol, 85 °C), this reaction produced a range of simple and substituted arylboronate pinacol esters in high yield and without biaryl side products.
- ?koch, Karel,Schulz, Ji?í,Císa?ová, Ivana,?těpni?ka, Petr
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p. 3060 - 3073
(2019/08/20)
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- Group 4 Post-Metallocenes Supported by [OCH2 N,C(σ-aryl)] Auxiliaries Bearing a Seven-Membered Metallacycle: Synthesis, Characterization, and Catalysts for Olefin Polymerization
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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
- Liu, Cham-Chuen,Liu, Qian,Yiu, Shek-Man,Chan, Michael C. W.
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supporting information
p. 2963 - 2971
(2019/08/22)
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- Method for catalyzing deaminized boric acid esterification or halogenation of arylamine
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The invention belongs to the technical field of organic synthesis and in particular discloses a method for catalyzing deaminized boric acid esterification or halogenation of arylamine. The method comprises the following steps: putting arylamine and a nitroso type compound into a mixed solvent, and performing a reaction at 0-5 DEG; and further adding a raw material capable of providing a functionalization group A and a catalysis amount of a reaction accelerator, and performing deamination functionalization reaction under light radiation at 10-50 DEG C, so as to obtain a product that an amino site of the arylamine is modified by the functionalization group A. Due to synergetic control on substrates, reaction solvents, material mixing modes, temperatures, reaction accelerators and addition amounts, boric acid esterification or halogenation of arylamine, particularly electron donating substituted arylamine which is hard to treat effectively in technical schemes of the industry, can be achieved.
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Paragraph 0063; 0073-0075
(2020/01/12)
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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)
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Paragraph 0062; 0063; 0071; 0072; 0074
(2018/05/03)
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- An organic boron compound
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PROBLEM TO BE SOLVED: To provide a production method of an arylboronic acid ester with a wide range of application substrate, using no heavy metal.SOLUTION: An organic halogen compound represented by the general formula R-X (where, X is Br or I; R is a C1 to 20 alkyl group, a C6 to 14 aryl group, a heterocyclic group comprising 1 to 3 hetero atoms selected from N, O and S, or the like) and a compound represented by the general formula (VI) are reacted in the presence of sodium alkoxide or potassium alkoxide for substitution of a substituted Si moiety and the R moiety to obtain arylboronic acid ester. (In the formula, three Rare each independently a C1 to 6 alkyl group or a C6 to 10 aryl group; and four Reach independently a C1 to 3 alkyl group.)
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Paragraph 0072-0074; 0096-0097
(2019/02/20)
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- COMPOUND FOR ORGANIC ELECTRONIC ELEMENT, ORGANIC ELECTRONIC ELEMENT USING THE SAME, AND A ELECTRONIC DEVICE THEREOF
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The present invention relates to a compound for an organic electronic element including a benzo fluorine compound and a derivative thereof, an organic electronic element utilizing the same, and an electronic device thereof. According to the present invention, the light emitting efficiency, the color purity, and the lifetime of the organic electronic element can be improved. [Reference numerals] (401) Substrate;(402) Anode;(404) Hole transport layer;(405) Light emitting layer;(406) Electron transport layer;(408) Cathode
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Paragraph 0084; 0087; 0127-0129
(2018/10/24)
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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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- Selective Photocatalytic C-F Borylation of Polyfluoroarenes by Rh/Ni Dual Catalysis Providing Valuable Fluorinated Arylboronate Esters
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A highly selective and general photocatalytic C-F borylation protocol that employs a rhodium biphenyl complex as a triplet sensitizer and the nickel catalyst [Ni(IMes)2] (IMes = 1,3-dimesitylimidazoline-2-ylidene) for the C-F bond activation and defluoroborylation process is reported. This tandem catalyst system operates with visible (blue, 400 nm) light and achieves borylation of a wide range of fluoroarenes with B2pin2 at room temperature in excellent yields and with high selectivity. Direct irradiation of the intermediary C-F bond oxidative addition product trans-[NiF(ArF)(IMes)2] leads to very fast decomposition when B2pin2 is present. This destructive pathway can be bypassed by indirect excitation of the triplet states of the nickel(II) complex via the photoexcited rhodium biphenyl complex. Mechanistic studies suggest that the exceptionally long-lived triplet excited state of the Rh biphenyl complex used as the photosensitizer allows for efficient triplet energy transfer to trans-[NiF(ArF)(IMes)2], which leads to dissociation of one of the NHC ligands. This contrasts with the majority of current photocatalytic transformations, which employ transition metals as excited state single electron transfer agents. We have previously reported that C(arene)-F bond activation with [Ni(IMes)2] is facile at room temperature, but that the transmetalation step with B2pin2 is associated with a high energy barrier. Thus, this triplet energy transfer ultimately leads to a greatly enhanced rate constant for the transmetalation step and thus for the whole borylation process. While addition of a fluoride source such as CsF enhances the yield, it is not absolutely required. We attribute this yield-enhancing effect to (i) formation of an anionic adduct of B2pin2, i.e., FB2pin2-, as an efficient, much more nucleophilic {Bpin-} transfer reagent for the borylation/transmetalation process, and/or (ii) trapping of the Lewis acidic side product FBpin by formation of [F2Bpin]- to avoid the formation of a significant amount of NHC-FBpin and consequently decomposition of {Ni(NHC)2} species in the reaction mixture.
- Tian, Ya-Ming,Guo, Xiao-Ning,Kuntze-Fechner, Maximilian W.,Krummenacher, Ivo,Braunschweig, Holger,Radius, Udo,Steffen, Andreas,Marder, Todd B.
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supporting information
p. 17612 - 17623
(2019/01/04)
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- Metal-Free Radical Borylation of Alkyl and Aryl Iodides
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A metal-free radical borylation of alkyl and aryl iodides with bis(catecholato)diboron (B2cat2) as the boron source under mild conditions is introduced. The borylation reaction is operationally easy to conduct and shows high functional group tolerance and broad substrate scope. Radical clock experiments and density functional theory calculations provide insights into the mechanism and rate constants for C-radical borylation with B2cat2 are disclosed.
- Cheng, Ying,Mück-Lichtenfeld, Christian,Studer, Armido
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supporting information
p. 16832 - 16836
(2018/11/23)
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- Copper-Catalyzed Monoorganylation of Trialkyl Borates with Functionalized Organozinc Pivalates
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Organozinc pivalates, a recently developed air- and moisture-stable organozinc species, were found for the first time as excellent organometallic species in the monoorganylation of trialkyl borates whereby boronic acids were prepared in high yields. The significant advantage of organozinc pivalates over another previously employed organometallic reagents, e. g., organolithium reagents, Grignard reagents and organozinc halides, is that the generation of multiorganylation byproducts such as borinic acids and trialkylboranes were completely suppressed. Additionally, the in situ generated boronates could be directly arranged into Suzuki-Miyaura type cross-coupling reactions to produce biaryls in high yields.
- Fu, Ying,Gou, Bei-Lei,Shi, Chun-Zhao,Du, Zhengyin,Shen, Tong
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p. 4253 - 4257
(2018/09/18)
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