cas 195062-57-8, 4-(4,4,5,5-TETRAMETHYL-1,3,2-DIOXABOROLAN-2-YL)TOLUENE

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Synthesis and structures of anionic rhenium polyhydride complexes of boron-hydride ligands and their application in catalysis
The rhenium complex, [K(DME)(18-c-6)][ReH4(Bpin)(η2-HBpin)(κ2-H2Bpin)] 1, comprising hydride and boron ligands only, has been synthesized by exhaustive deoxygenation of the commercially available perrhenate anion (ReO4-) with pinacol borane (HBpin). The structure of 1 was analysed by X-ray crystallography, NMR spectroscopy, and DFT calculations. While no hydrides were located in the X-ray crystal structure, it revealed a trigonal arrangement of pinacol boron ligands. Variable-temperature NMR spectroscopy supported the presence of seven hydride ligands but further insight was hindered by the fluxionality of both hydride and boron ligands at low temperature. Further evaluation of the structure by Ab Initio Random Structure Searching (AIRSS) identified the presence of hydride, boryl, σ-borane, and dihydroborate ligands. This complex, either isolated or prepared in situ, is a catalyst for the 1,4-hydroboration of N-heteroaromatic substrates under simple operating procedures. It also acts as a reagent for the stoichiometric C-H borylation of toluene, displaying high meta regioselectivity in the borylated products. Reaction of 1 with 9-BBN resulted in HBpin substitution to form the new anionic tetra(dihydroborate) complex [K(DME)(18-c-6)][Re(κ2-H-9-BBN)4] 4 for which the hydride positions were clearly identified by X-ray crystallography. The method used to generate these isolable yet reactive boron-hydride complexes is direct and straightforward and has potential utility for the exploitation of other metal oxo compounds in operationally simple catalytic reactions.
Donnelly, Liam J.,Love, Jason B.,Morrison, Carole A.,Parsons, Simon,Thomas, Stephen P.
p. 9994 - 9999
(2020)
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Palladium-catalyzed arylboration of bicyclic alkenes
A palladium-catalyzed arylboration of norbornene or norbornadiene with aryl halides and bis(pinacolato)diboron has been disclosed. Mechanistic studies suggest that the reaction proceeds under a Catellani-type coupling to render versatile multifunctionaliz
Yang, Kai,Song, Qiuling
p. 1000 - 1005
(2016)
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Mechanistic Insights into C-H Borylation of Arenes with Organoiridium Catalysts Embedded in a Microporous Metal-Organic Framework
Organometallic iridium catalysts can be used in conjunction with bispinacolatodiboron (B2Pin2) to effect the borylation of a variety of substrates such as arenes, alkanes, heteroarenes, and oxygenates. Recently, efforts have also focused on integrating these catalysts into porous supports, such as metal-organic frameworks (MOFs). While the mechanism of homogeneous borylation systems has been thoroughly investigated experimentally and computationally, analogous studies in MOF-supported iridium catalysts have not been conducted. Herein, we report the mechanistic investigation of a phenanthroline-iridium catalyst immobilized in the organic linker of Universitetet i Oslo (UiO)-67 (Zr6O4(OH)4(BPDC)4(PhenDC)2, BPDC = biphenyl-4,4′-dicarboxylate, PhenDC = 1,10-phenanthroline-4,4′-dicarboxylate). By using benzene as a model substrate, variable time normalization analysis (VTNA) of the kinetic data suggested a rate law consistent with zero-order in B2Pin2, and first-order in arene. A primary kinetic isotope effect (KIE) in the time course of benzene-d6 borylation also provided complementary information about the role of the arene in the rate-determining step of the reaction. Characterization by techniques such as X-ray absorption spectroscopy (XAS) confirmed the presence of Ir(III), while pair distribution function (PDF) analysis suggested structures containing an Ir-Cl bond, further substantiated by X-ray photoelectron spectroscopy (XPS). Analysis of postcatalysis materials by inductively coupled plasma-optical emission spectroscopy (ICP-OES) revealed low boron accumulation, which may indicate an absence of boron in the resting state of the catalyst. Finally, in comparing borylation of benzene and toluene, a slight selectivity for benzene is observed, which is similar to the analogous homogeneous reaction, indicating the influence of substrate sterics on reactivity.
Chapman, Karena W.,Chen, Zhihengyu,Delferro, Massimiliano,Farha, Omar K.,Goetjen, Timothy A.,Idrees, Karam B.,Kaphan, David M.,Syed, Zoha H.,Wegener, Evan C.,Zhang, Xuan
(2020)
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Phototransposition reactions of arylboronate esters in acetonitrile and 2,2,2-trifluoroethanol
The phototransposition (para, meta, ortho) reactions of the arylboronate esters 4-, 3-, and 2-(4′,4′,5′,5′-tetramethyl-1′, 3′,2′-dioxaborolanyl)toluenes (1,2, and 3, respectively) in both acetonitrile and 2,2,2-trifluoroethanol (TFE) using 254 nm irradiation have been examined. The irradiations resulted in steady-state compositions of para (5%), meta (19%), and ortho (76%) isomers in acetonitrile starting from the ortho isomer and para (12%), meta (54%), and ortho (35%) isomers in TFE starting from the para isomer. Analysis of the 13C NMR spectrum of the product mixture obtained from the photochemistry of the para isomer selectively deuterated at C3 and C5 (1d2) revealed that the boron-substituted carbon is the active one in the phototransposition reactions in both acetonitrile and TFE. Similar results were observed for irradiations of 1 in cyclohexane. Fluorescence spectra, singlet-state lifetimes, and Stern-Volmer quenching of fluorescence with 2,3-dimethyl-1,3-butadiene indicated that the excited singlet states of these three isomers were spectroscopic minima and that the excited singlet state was the reactive one for 3 in acetonitrile.
Cameron,Pincock,Pincock,Thompson
p. 4954 - 4960
(2004)
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Rhodium and iridium complexes of N-heterocyclic carbenes: Structural investigations and their catalytic properties in the borylation reaction
Bridged and unbridged N-heterocyclic carbene (NHC) ligands are metalated with [Ir/Rh(COD)2Cl]2 to give rhodium(I/III) and iridium(I) mono- and biscarbene substituted complexes. All complexes were characterized by spectroscopy, in addition [Ir(COD)(NHC)2][Cl,I] [COD = 1,5-cyclooctadiene, NHC = 1,3-dimethyl- or 1,3-dicyclohexylimidazolin-2-ylidene] (1, 4), and the biscarbene chelate complexes 12 [(η4-1,5-cyclooctadiene)(1,1′-di-n-butyl-3,3′-ethylene-diimidazolin-2,2′-diylidene)iridium(I) bromide] and 14 [(η4-1,5-cyclooctadiene)(1,1′-dimethyl-3,3′-o-xylylene-diimidazolin-2,2′-diylidene)iridium(I) bromide] were characterized by single crystal X-ray analysis. The relative σ-donor/π-acceptor qualities of various NHC ligands were examined and classified in monosubstituted NHC-Rh and NHC-Ir dicarbonyl complexes by means of IR spectroscopy. For the first time, bis(carbene) substituted iridium complexes were used as catalysts in the synthesis of arylboronic acids starting from pinacolborane and arene derivatives.
Frey, Guido D.,Rentzsch, Christoph F.,von Preysing, Denise,Scherg, Tobias,Mühlhofer, Michael,Herdtweck, Eberhardt,Herrmann, Wolfgang A.
p. 5725 - 5738
(2006)
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Aromatic C-H borylation by nickel catalysis
The first nickel-catalyzed aromatic C-H borylation is described. In the presence of catalytic amounts of [Ni(cod)2], tricyclopentylphosphine, and CsF, benzene and indole derivatives can be borylated with B2pin2. The N-heterocyclic carbene IPr was also found to be an effective ligand. Kinetic isotope effect experiments showed that C-H cleavage is likely involved in the rate-determining step.
Zhang, Hua,Hagihara, Shinya,Itami, Kenichiro
p. 779 - 781
(2015)
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Polymer-supported, photo-redox catalysts prepared from unimolecular photo-redox catalyst/initiator systems
Unimolecular, photo-redox catalyst/initiator systems can effectively synthezise their own polymer-support that can then be used to affect recovery and reuse of the resulting supported catalyst. We show that α-bromo ester-containing Ru(bpy)3- and phenothiazine-derivatives (common photo-redox catalysts) can undergo visible light-facilitated radical polymerizations to form polymer-supported photo-redox catalysts that can facilitate photo-redox [2+2] cycloadditions and metal-free borylations in a recyclable manner.
Peavy, Matthew,Hobbs, Christopher
(2021)
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Cobalt-Catalyzed C(sp2)-H Borylation: Mechanistic Insights Inspire Catalyst Design
A comprehensive study into the mechanism of bis(phosphino)pyridine (PNP) cobalt-catalyzed C-H borylation of 2,6-lutidine using B2Pin2 (Pin = pinacolate) has been conducted. The experimentally observed rate law, deuterium kinetic isotope effects, and identification of the catalyst resting state support turnover limiting C-H activation from a fully characterized cobalt(I) boryl intermediate. Monitoring the catalytic reaction as a function of time revealed that borylation of the 4-position of the pincer in the cobalt catalyst was faster than arene borylation. Cyclic voltammetry established the electron withdrawing influence of 4-BPin, which slows the rate of C-H oxidative addition and hence overall catalytic turnover. This mechanistic insight inspired the next generation of 4-substituted PNP cobalt catalysts with electron donating and sterically blocking methyl and pyrrolidinyl substituents that exhibited increased activity for the C-H borylation of unactivated arenes. The rationally designed catalysts promote effective turnover with stoichiometric quantities of arene substrate and B2Pin2. Kinetic studies on the improved catalyst, 4-(H)2BPin, established a change in turnover limiting step from C-H oxidative addition to C-B reductive elimination. The iridium congener of the optimized cobalt catalyst, 6-(H)2BPin, was prepared and crystallographically characterized and proved inactive for C-H borylation, a result of the high kinetic barrier for reductive elimination from octahedral Ir(III) complexes.
Obligacion, Jennifer V.,Semproni, Scott P.,Pappas, Iraklis,Chirik, Paul J.
p. 10645 - 10653
(2016)
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Facile cyclometallation of a mesitylsilylene: Synthesis and preliminary catalytic activity of iridium(III) and iridium(v) iridasilacyclopentenes
Reactions of the mesityl-amidinato-silylene Si(tBu2bzam)Mes (1; tBu2bzam = N,N′-bis(tert-butyl)benzamidinato; Mes = mesityl) with three different iridium precursors led, at room temperature, to two iridium(iii) and one iridium(v) complexes featuring one (IrIII) or two (IrV) cyclometallated silylene ligands. The iridium(iii) complexes are active catalyst precursors for H/D exchange and dehydrogenative borylation of arene C-H bonds.
Cabeza, Javier A.,García-álvarez, Pablo,González-álvarez, Laura
p. 10275 - 10278
(2017)
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Recyclable Pd2dba3/XPhos/PEG-2000 System for Efficient Borylation of Aryl Chlorides: Practical Access to Aryl Boronates
Pd2dba3/XPhos in poly(ethylene glycol) (PEG-2000) is shown to be a highly stable and efficient catalyst for the borylation of aryl chlorides with bis(pinacolato)diboron. The borylation reaction proceeds smoothly at 110 °C, delivering a wide variety of aryl boronates in good to excellent yields with high functional group tolerance. The crude products were easily isolated via simple extraction of the reaction mixture with cyclohexane. Moreover, both expensive Pd2dba3 and XPhos in PEG-2000 system could be readily recycled and reused more than six times without loss of catalytic efficiency.
Cai, Mingzhong,Luo, Chengkai,Xu, Caifeng,Huang, Bin
p. 1339 - 1346
(2021/12/02)

Palladium-catalyzed borylation of aryl bromides and chlorides using phosphatrioxa-adamantane ligands
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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(2021/12/13)

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
supporting information

(2022/03/15)

Photochemical and electrochemical C-N borylation of arylhydrazines
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)

Remote steric control for undirected meta-selective C-H activation of arenes
Regioselective functionalization of arenes remains a challenging problem in organic synthesis. Steric interactions are often used to block sites adjacent to a given substituent, but they do not distinguish the remaining remote sites. We report a strategy
Asako, Sobi,Ilies, Laurean,Jin, Yushu,Ramadoss, Boobalan
p. 658 - 663
(2022/02/21)

Cu-mediated: vs. Cu-free selective borylation of aryl alkyl sulfones
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.
supporting information
p. 395 - 398
(2022/01/19)

Unreactive C-N Bond Activation of Anilines via Photoinduced Aerobic Borylation
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
supporting information
p. 64 - 68
(2021/12/27)

Photo-induced thiolate catalytic activation of inert Caryl-hetero bonds for radical borylation
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
supporting information
p. 1653 - 1665
(2021/06/17)

Arene borylation through C–H activation using Cu3(BTC)2 as heterogeneous catalyst
C–H borylation by diborane is an important process to access organoboron compounds. Noble metals, including Ir and Rh-based complexes either in the form of homogeneous or heterogeneous catalysts, have been reported to promote arene C–H borylation. Recently, metal organic frameworks (MOFs) having Ir and Co as active sites have been used as catalysts, but they require co-catalysts. In the present study, commercially available Cu3(BTC)2 (BTC: 1,3,5-benzenetricarboxylate) MOF is reported as an effective catalyst to promote borylation of arenes through C–H activation employing bis(pinacolato)diboron (1) as reagent leading to benzylic and aromatic borylation products. Interestingly, other related MOFs like MIL-101(Cr) and Al(OH)(BDC) (BDC: 1,4-benzenedicarboxylate) do not exhibit catalytic activity under identical conditions. Mechanistic studies using in-situ IR spectroscopy reveal that Cu ions play a crucial role in activating the arene and B–B bond in 1.
Dhakshinamoorthy, Amarajothi,García, Cristina Vallés,Concepcion, Patricia,Garcia, Hermenegildo
p. 212 - 217
(2020/07/06)

Zinc Complexes with an Ethylene-Bridged Bis(β-diketiminate) Ligand: Syntheses, Structures, and Applications as Catalysts in the Borylation of Aryl Iodides
A dinucleating bis(β-diketiminate) ligand with a flexible bridge has been employed to synthesize zinc complexes. The ligand, abbreviated H2L (H2L = N-(4-((2-((4-((2,6-diisopropylphenyl)imino)pent-2-en-2-yl)amino)ethyl)imino)pent-2-en-2-yl)-2,6-diisopropylaniline), was deprotonated with ZnEt2 to afford [LZn2Et2] (1). Reactions of 1 with 2 equiv of BnOH and nBuOH, respectively, gave access to [LZn2(OBn)2]·C6H14 (2·C6H14) and [LZn2(OnBu)2] (3). Treatment of 1 with 2 equiv of I2 in THF produced [LZn2I2(THF)2]·2THF (4·2THF). X-ray single-crystal diffraction analyses revealed that they are all heteroleptic bimetallic compounds with two metal centers being chelated by one ligand set. The structurally similar compounds 1 and 4·2THF possess approximate C2 symmetry, with two β-diketiminate units being arrayed in head-to-tail antiparallel mode. Thus, the molecular structures of 1 and 4·2THF exhibit a seesaw-like topology. The structures of 2·C6H14 and 3 are almost identical, in which two zinc atoms are shared by two ZnN2C3 six-membered rings, two Zn2ON2C2 seven-membered rings, and one Zn2O2 four-membered ring. Therefore, the metal cores of 2·C6H14 and 3 display a crownlike topology. All complexes are catalytically active for the borylation of aryl iodides with B2Pin2 (B2Pin2 = 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bis(1,3,2-dioxaborolane). Complex 1 shows higher activity in comparison to 2, 3, and 4·2THF. The borylation reactions catalyzed by 1 could proceed under mild conditions and can be applied to a series of substrates with high functional group generality. This methodology thus represents a novel use of β-diketiminate zinc complexes for C-I borylation.
Li, Yafei,Dang, Yan,Li, Dawei,Pan, Huifen,Zhang, Liang,Wang, Li,Cao, Zhu,Li, Yahong
supporting information
p. 482 - 489
(2021/03/01)

DRUG AND GENE THERAPY TO TREAT HIGH MYOPIA AND OTHER OCULAR DISORDERS WITH ENLARGED EYE GLOBES
This invention relates to a treatment of various eye conditions relating to eye enlargement. The conditions can be treated by inhibiting an upstream protein within the said biological pathway or by increasing the expression of a downstream receptor within
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(2021/12/29)

Evaluation of the role of graphene-based Cu(i) catalysts in borylation reactions
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
p. 3501 - 3513
(2021/06/06)

One-pot synthesis of Ag-Cu-Cu2O/C nanocomposites derived from a metal-organic framework as a photocatalyst for borylation of aryl halide
Mixed metal-metal oxide/C (Ag-Cu-Cu2O/C) nanocomposites were synthesized by the heat treatment of a metal-organic framework under a N2 flow using the one-pot synthesis method. The as-prepared nanocomposites were characterized using a range of techniques,
Annas, Dicky,Bae, Jong-Seong,Hira, Shamim Ahmed,Park, Kang Hyun,Park, Sungkyun,Song, Sehwan
p. 32965 - 32972
(2021/12/07)

Preparation method of aryl borate catalyzed by cesium neovalerate
The preparation method comprises the following steps: dissolving a compound of formula (I) and a diboron compound in an organic solvent, then adding an organic solvent dissolved with cesium neovalerate, palladium acetate and triphenylphosphine, and carrying out reaction to obtain aryl boronic acid ester. In the formula (I) R1. R2, R3, R4 and R5 are each independently selected from H, C. 1 - C10 Alkyl group, C2 - C10 Alkenyl, C2 - C10 Alkynyl group, C1 - C10 Alkoxy, hydroxy, hydroxy-substituted C1 - C10 Alkyl, phenyl, C1 - C10 Alkylamino. X Is selected from F, Cl, Br, i. The preparation method has the advantages of low production cost, high product yield, high purity, simple operation and suitability for industrial mass production.
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(2021/09/22)

Remarkably Efficient Iridium Catalysts for Directed C(sp2)-H and C(sp3)-H Borylation of Diverse Classes of Substrates
Here we describe the discovery of a new class of C-H borylation catalysts and their use for regioselective C-H borylation of aromatic, heteroaromatic, and aliphatic systems. The new catalysts have Ir-C(thienyl) or Ir-C(furyl) anionic ligands instead of the diamine-type neutral chelating ligands used in the standard C-H borylation conditions. It is reported that the employment of these newly discovered catalysts show excellent reactivity and ortho-selectivity for diverse classes of aromatic substrates with high isolated yields. Moreover, the catalysts proved to be efficient for a wide number of aliphatic substrates for selective C(sp3)-H bond borylations. Heterocyclic molecules are selectively borylated using the inherently elevated reactivity of the C-H bonds. A number of late-stage C-H functionalization have been described using the same catalysts. Furthermore, we show that one of the catalysts could be used even in open air for the C(sp2)-H and C(sp3)-H borylations enabling the method more general. Preliminary mechanistic studies suggest that the active catalytic intermediate is the Ir(bis)boryl complex, and the attached ligand acts as bidentate ligand. Collectively, this study underlines the discovery of new class of C-H borylation catalysts that should find wide application in the context of C-H functionalization chemistry.
Chattopadhyay, Buddhadeb,Hassan, Mirja Md Mahamudul,Hoque, Md Emdadul
supporting information
p. 5022 - 5037
(2021/05/04)

Cross-Coupling through Ag(I)/Ag(III) Redox Manifold
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
supporting information
p. 15396 - 15405
(2021/10/12)

Catalytic Boration of Alkyl Halides with Borane without Hydrodehalogenation Enabled by Titanium Catalyst
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
supporting information
p. 12298 - 12303
(2021/05/07)

Method for catalytically synthesizing phenylboronic acid ester derivative by iridium catalyst
The invention relates to a method for catalytically synthesizing a phenylboronic acid ester derivative by using an iridium catalyst. The method comprises the following steps: by using a cyclooctadieneiridium chloride dimer as a catalyst, dissolving aryl halide and pinacol borane in an organic solvent to react, and carrying out aftertreatment to obtain the phenylboronic acid ester derivative. Compared with the prior art, the method has the advantages that the method is simple and green, cheap, readily available and stable raw materials of aryl halide and pinacol borane are used, the reaction conditions are mild, corresponding products can be obtained at high yield through reaction at room temperature in a non-inert atmosphere, and the method has good substrate universality, so that the method is better convenient to apply.
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(2021/01/11)

Unveiling Extreme Photoreduction Potentials of Donor-Acceptor Cyanoarenes to Access Aryl Radicals from Aryl Chlorides
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
supporting information
p. 13266 - 13273
(2021/09/07)

The functionalization of benzene by boranes using trispyrazolylborate complexes
The catalytic C[sbnd]H activation and borylation of arenes by trispyrazolylborate complexes is reported. Trispyrazolylborate rhodium and iridium complexes have been previously shown to activate a variety of C[sbnd]H bonds. Here, we show the catalytic borylation of arenes by the trispyrazolylborate ethylene complexes Tp'Rh(C2H4)2, and Tp'Ir(C2H4)2.
Vetter, Andrew J.,DiBenedetto, Tarah A.,Ritz, Mikhaila D.,Jones, William D.
(2021/02/03)

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
(2021/11/04)

Metal-Organic Framework-Confined Single-Site Base-Metal Catalyst for Chemoselective Hydrodeoxygenation of Carbonyls and Alcohols
Chemoselective deoxygenation of carbonyls and alcohols using hydrogen by heterogeneous base-metal catalysts is crucial for the sustainable production of fine chemicals and biofuels. We report an aluminum metal-organic framework (DUT-5) node support cobalt(II) hydride, which is a highly chemoselective and recyclable heterogeneous catalyst for deoxygenation of a range of aromatic and aliphatic ketones, aldehydes, and primary and secondary alcohols, including biomass-derived substrates under 1 bar H2. The single-site cobalt catalyst (DUT-5-CoH) was easily prepared by postsynthetic metalation of the secondary building units (SBUs) of DUT-5 with CoCl2 followed by the reaction of NaEt3BH. X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy (XANES) indicated the presence of CoII and AlIII centers in DUT-5-CoH and DUT-5-Co after catalysis. The coordination environment of the cobalt center of DUT-5-Co before and after catalysis was established by extended X-ray fine structure spectroscopy (EXAFS) and density functional theory. The kinetic and computational data suggest reversible carbonyl coordination to cobalt preceding the turnover-limiting step, which involves 1,2-insertion of the coordinated carbonyl into the cobalt-hydride bond. The unique coordination environment of the cobalt ion ligated by oxo-nodes within the porous framework and the rate independency on the pressure of H2 allow the deoxygenation reactions chemoselectively under ambient hydrogen pressure.
Antil, Neha,Kumar, Ajay,Akhtar, Naved,Newar, Rajashree,Begum, Wahida,Manna, Kuntal
supporting information
p. 9029 - 9039
(2021/06/28)

METHOD FOR SYNTHESIZING BORONATE ESTER COMPOUND, SODIUM SALT OF BORONATE ESTER COMPOUND, AND METHOD FOR SYNTHESIZING THE SAME
An object is to establish a technology with which a boronate ester compound can be easily and efficiently synthesized at a low cost with a small number of steps without the need for a complex chemical method and reagents that need to be carefully handled. A further object is to establish a sodium salt of a boronate ester compound that is a novel compound and a technology for synthesizing the sodium salt of a boronate ester compound. Provided are a sodium salt of a boronate ester compound and a method for synthesizing a boronate ester compound or a sodium salt of a boronate ester compound that includes reacting, in a reaction solvent, an organic chloride with a dispersion product obtained by dispersing sodium in a dispersion solvent to obtain an organic sodium compound, and reacting the obtained organic sodium compound with a borate ester compound to obtain a boronate ester compound or a sodium salt of a boronate ester compound.
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Paragraph 0112

(2021/03/13)

Improvement in the Palladium-Catalyzed Miyaura Borylation Reaction by Optimization of the Base: Scope and Mechanistic Study
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.
supporting information
p. 103 - 109
(2020/12/22)

Electrochemical Thiolation and Borylation of Arylazo Sulfones with Thiols and B2pin2
An efficient electrochemical synthesis approach of various unsymmetrical thioethers and arylboronates has been developed. Bench stable arylazo sulfones were used as radical precursors for carbon-heteroatom bond formation under electrochemical conditions. Moreover, the scalability of this approach was evaluated by performing the electrochemical thiolation and borylation of arylazo sulfones with thiols and B2pin2 on a gram scale. This protocol not only avoided the use of stoichiometric oxidants, metal catalysts, activating agents and even added bases, but also exhibited favorable functional group tolerance. (Figure presented.).
Wang, Rongkang,Chen, Fangming,Jiang, Lvqi,Yi, Wenbin
supporting information
p. 1904 - 1911
(2021/02/12)

End-Functionalization of Diarylethene for Opto-Electronic Switching with High Fatigue Resistance
A molecular and synthetic approach to strengthen the switching performance of diarylethene (DAE)-based organic transistors is proposed. By tuning the length of alkyl side chains of the biphenyl unit attached to 1,2-bis(5-biphenyl-2-methylthien-3-yl)perfluorocyclopentene (DAE), we show that the molecular environment for reversible photoisomerization of DAEs can be optimized. Four different DAEs are synthesized with different alkyl chains (DAE_C0, DAE_C1, DAE_C6, and DAE_C10), and ITIC is chosen to construct a semiconductor matrix to maximize the quantum yield of photoconversion considering the complementary absorption range of both materials. From photophysical, structural, and morphological analyses, the longer alkyl chains inhibit intermolecular aggregation between DAEs and allow more hydrophobic surface properties of DAEs, thus improving molecular miscibility with ITIC. The improved molecular compatibility of DAEs with ITIC makes the overall bulk heterojunction film amorphous, allowing more free volume for reversible photoisomerization. Consequently, DAE_C6 exhibits the maximum quantum yield for both photocyclization and photocycloreversion, enabling high light-controlled on/off ratios in photoswitchable transistors. Furthermore, the exceptionally high DAE_C6 quantum yield enables robust fatigue resistance under repeated photoswitching with only a 30% decrease in the on/off ratio after 100 cycles. Overall, this work shows that not only the energy level but also the molecular compatibility can endow significant switching performances for molecular switches.
Hassan, Syed Zahid,Yu, Seong Hoon,So, Chan,Moon, Dohyun,Chung, Dae Sung
p. 403 - 412
(2021/01/13)

Light- and Manganese-Initiated Borylation of Aryl Diazonium Salts: Mechanistic Insight on the Ultrafast Time-Scale Revealed by Time-Resolved Spectroscopic Analysis
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)

Carbon-carbon bond activation by B(OMe)3/B2pin2-mediated fragmentation borylation
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
p. 15104 - 15109
(2021/12/09)

Rh-Catalyzed Base-Free Decarbonylative Borylation of Twisted Amides
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
p. 15676 - 15685
(2020/11/13)

Visible Light-Induced Borylation of C-O, C-N, and C-X Bonds
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.
supporting information

(2020/02/04)

Photocatalytic C–X borylation of aryl halides by hierarchical SiC nanowire-supported Pd nanoparticles
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
p. 357 - 363
(2019/12/28)

Luminescent tungsten(vi) complexes as photocatalysts for light-driven C-C and C-B bond formation reactions
The realization of photocatalysis for practical synthetic application hinges on the development of inexpensive photocatalysts which can be prepared on a large scale. Herein an air-stable, visible-light-absorbing photoluminescent tungsten(vi) complex which can be conveniently prepared at the gram-scale is described. This complex could catalyse photochemical organic transformation reactions including borylation of aryl halides, such as aryl chloride, reductive coupling of benzyl bromides for C-C bond formation, reductive coupling of phenacyl bromides, and decarboxylative coupling of redox-active esters of alkyl carboxylic acid with high product yields and broad functional group tolerance.
Chan, Kaai-Tung,Che, Chi-Ming,Du, Lili,Liu, Yungen,Phillips, David Lee,To, Wai-Pong,Tong, Glenna So Ming,Wu, Liang-Liang,Yu, Daohong
p. 6370 - 6382
(2020/07/15)

Direct C?H Borylation of Arenes Catalyzed by Saturated Hydride-Boryl-Iridium-POP Complexes: Kinetic Analysis of the Elemental Steps
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
supporting information
p. 12632 - 12644
(2020/09/09)

Undirected ortho-selectivity in C–H borylation of arenes catalyzed by NHC platinum(0) complexes
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.
p. 569 - 571
(2020/10/09)

Facile and economical Miyaura borylation and one-pot Suzuki–Miyaura cross-coupling reaction
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
(2020/03/03)

Visible-light-mediated borylation of aryl and alkyl halides with a palladium complex
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)

Iron-catalysed enantioconvergent Suzuki-Miyaura cross-coupling to afford enantioenriched 1,1-diarylalkanes
The first stereoconvergent Suzuki-Miyaura cross-coupling reaction was developed to afford enantioenriched 1,1-diarylalkanes. An iron-based complex containing a chiral cyanobis(oxazoline) ligand framework was best to obtain enantioenriched 1,1-diarylalkanes from cross-coupling reactions between unactivated aryl boronic esters and benzylic chlorides. Enhanced yields were obtained when 1,3,5-trimethoxybenzene was used as an additive, which is hypothesized to extend the lifetime of the iron-based catalyst. Exceptional enantioselectivities were obtained with challenging ortho-substituted benzylic chlorides. This journal is
Tyrol, Chet C.,Yone, Nang S.,Gallin, Connor F.,Byers, Jeffery A.
supporting information
p. 14661 - 14664
(2020/12/02)

Visible-Light-Induced Ni-Catalyzed Radical Borylation of Chloroarenes
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)

Transformations of Aryl Ketones via Ligand-Promoted C?C Bond Activation
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
p. 14388 - 14393
(2020/07/06)

Pd-Catalyzed Site-Selective Borylation of Simple Arenes via Thianthrenation?
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
p. 1269 - 1272
(2020/08/13)

Development and Mechanistic Studies of Iron-Catalyzed Construction of Csp2-B Bonds via C-O Bond Activation
Herein we describe an iron-catalyzed borylation of alkenyl and aryl carbamates through the activation of a C-O bond. This protocol exhibits high efficiency, a broad substrate scope, and the late-stage borylation of biorelevant compounds, thus providing potential applications in medicinal chemistry. Moreover, this method enables orthogonal transformations of phenol derivatives and also offers good opportunities for the synthesis of multisubstituted arenes. Preliminary mechanistic studies suggest that a FeII/FeIII catalytic cycle via a radical pathway might be involved in the reaction.
Geng, Shasha,Zhang, Juan,Chen, Shuo,Liu, Zhengli,Zeng, Xiaoqin,He, Yun,Feng, Zhang
p. 5582 - 5588
(2020/07/08)

Visible- And UV-Light-Induced Decarboxylative Radical Reactions of Benzoic Acids Using Organic Photoredox Catalysts
Photoinduced decarboxylative radical reactions of benzoic acids with electron-deficient alkenes, diborane, and acetonitrile under organic photoredox catalysis conditions and mild heating afforded adducts, arylboronate esters, and the reduction product, respectively. The reaction is thought to involve single-electron transfer promoted the generation of aryl radicals via decarboxylation. A diverse range of benzoic acids were found to be suitable substrates for this photoreaction. Only our two-molecule organic photoredox system can work well for the direct photoinduced decarboxylation of benzoic acids.
Kubosaki, Suzuka,Takeuchi, Haruka,Iwata, Yutaka,Tanaka, Yosuke,Osaka, Kazuyuki,Yamawaki, Mugen,Morita, Toshio,Yoshimi, Yasuharu
p. 5362 - 5369
(2020/05/19)

Radical C?N Borylation of Aromatic Amines Enabled by a Pyrylium Reagent
Herein, we report a radical borylation of aromatic amines through a homolytic C(sp2)?N bond cleavage. This method capitalizes on a simple and mild activation via a pyrylium reagent (ScPyry-OTf) thus priming the amino group for reacti
Chabbra, Sonia,Cornella, Josep,Leutzsch, Markus,Ma, Yuanhong,Niski, Jan,Pang, Yue,Reijerse, Edward J.,Schnegg, Alexander
supporting information

(2020/03/23)

Hydride Transfer Enables the Nickel-Catalyzed ipso-Borylation and Silylation of Aldehydes
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
supporting information
p. 423 - 427
(2019/12/27)

Para-selective borylation of monosubstituted benzenes using a transient mediator
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
p. 336 - 340
(2019/12/09)

Preparation method of aryl borate
The invention provides a preparation method of aryl borate. The method mainly comprises the following steps: in the presence of a water-soluble free radical initiator, reacting by using water as a solvent and aryl sulfonyl chloride and bis(pinacolato)diboron as raw materials, extracting by using an organic solvent after the reaction is completed, collecting an organic phase, and carrying out reduced pressure distillation to obtain the product aryl borate. According to the invention, the water-soluble free radical initiator is used, and water can be used as a reaction solvent, so that comparedwith the prior art that organic solvents such as acetonitrile, halogenated alkane and ethyl acetate are used, the method of the invention uses the water as the solvent, so that environmental pollutionis reduced, toxicity is reduced, and the raw material source is more economical; and the method has the advantages of being mild in reaction, simple in aftertreatment, high in yield, high in purity and the like, and is very suitable for industrial production.
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Paragraph 0048-0049; 0050-0051

(2020/10/30)

Preparation method of aryl borate
The invention provides a preparation method of aryl borate, which mainly comprises the following steps: in the presence of a water-soluble free radical initiator, reacting by using water as a solventand aryl sulfonyl chloride and bis(pinacolato)borate as raw materials, extracting the reaction product by using an organic solvent after the reaction is completed, collecting the extract an organic phase, and carrying out reduced pressure distillation to obtain the product aryl borate. By using the water-soluble free radical initiator, water can be used as a reaction solvent; compared with the prior art that acetonitrile, halogenated alkane, ethyl acetate and other organic solvents are used, water is used as a solvent, environmental pollution is reduced, toxicity is reduced, and raw material sources are more economical; in addition, the method has the advantages of mild reaction, simple post-treatment, high yield, high purity and the like, and is very suitable for industrial production.
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Paragraph 0048-0051

(2020/11/26)