- Stereoselective gem-C,B-Glycosylation via 1,2-Boronate Migration
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A novel protocol is established for the long-standing challenge of stereoselective geminal bisglycosylations of saccharides. The merger of PPh3 as a traceless glycosidic leaving group and 1,2-boronate migration enables the simultaneous introduction of C-C and C-B bonds at the anomeric stereogenic center of furanoses and pyranoses. The power of this method is showcased by a set of site-selective modifications of glycosylation products for the construction of bioactive conjugates and skeletons. A scarce metal-free 1,1-difunctionalization process of alkenes is also concomitantly demonstrated.
- He, Zhi-Tao,Li, Rui-Peng,Liao, Qi-Ying,Ma, Chao,Wang, Miao,Zhao, Wei-Cheng
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supporting information
p. 2460 - 2467
(2022/02/16)
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- Practical Synthesis of Allyl, Allenyl, and Benzyl Boronates through SN1′-Type Borylation under Heterogeneous Gold Catalysis
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Efficient borylation of sp3 C-O bonds by supported Au catalysts is described. Au nanoparticles supported on TiO2 showed high activity under mild conditions employing low catalyst loading conditions without the aid of any additives, such as phosphine and bases. A variety of allyl, propargyl, and benzyl substrates participated in the heterogeneously catalyzed reactions to furnish the corresponding allyl, allenyl, and benzyl boronates in high yields. Besides, Au/TiO2 was also effective for the direct borylation of allylic and benzylic alcohols. A mechanistic investigation based on a Hammett study and control experiments revealed that sp3 C-O bond borylation over supported Au catalysts proceeded through SN1′-type mechanism involving the formation of a carbocationic intermediate. The high activity, reusability, and environmental compatibility of the supported Au catalysts as well as the scalability of the reaction system enable the practical synthesis of valuable organoboron compounds.
- Miura, Hiroki,Hachiya, Yuka,Nishio, Hidenori,Fukuta, Yohei,Toyomasu, Tomoya,Kobayashi, Kosa,Masaki, Yosuke,Shishido, Tetsuya
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p. 758 - 766
(2021/02/03)
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- (o-Phenylenediamino)borylstannanes: Efficient Reagents for Borylation of Various Alkyl Radical Precursors
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(o-Phenylenediamino)borylstannanes were newly synthesized to achieve radical boryl substitutions of a variety of alkyl radical precursors. Dehalogenative, deaminative, decharcogenative, and decarboxylative borylations proceeded in the presence of a radica
- Suzuki, Kensuke,Nishimoto, Yoshihiro,Yasuda, Makoto
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supporting information
p. 3968 - 3973
(2020/12/30)
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- Photochemical Radical C–H Halogenation of Benzyl N-Methyliminodiacetyl (MIDA) Boronates: Synthesis of α-Functionalized Alkyl Boronates
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α-Haloboronates are useful organic synthons that can be converted to a diverse array of α-substituted alkyl borons. Methods to α-haloboronates are limiting and often suffer from harsh reaction conditions. Reported herein is a photochemical radical C-H halogenation of benzyl N-methyliminodiacetyl (MIDA) boronates. Fluorination, chlorination, and bromination reactions were effective by using this protocol. Upon reaction with different nucleophiles, the C?Br bond in the brominated product could be readily transformed to a series of C?C, C?O, C?N, C?S, C?P, and C?I bonds, some of which are difficult to forge with α-halo sp2-B boronate esters. An activation effect of B(MIDA) moiety was found.
- Yang, Ling,Tan, Dong-Hang,Fan, Wen-Xin,Liu, Xu-Ge,Wu, Jia-Qiang,Huang, Zhi-Shu,Li, Qingjiang,Wang, Honggen
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supporting information
p. 3454 - 3458
(2020/12/17)
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- Structure-Based Optimization and Discovery of M3258, a Specific Inhibitor of the Immunoproteasome Subunit LMP7 (β5i)
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Proteasomes are broadly expressed key components of the ubiquitin-dependent protein degradation pathway containing catalytically active subunits (β1, β2, and β5). LMP7 (β5i) is a subunit of the immunoproteasome, an inducible isoform that is predominantly expressed in hematopoietic cells. Clinically effective pan-proteasome inhibitors for the treatment of multiple myeloma (MM) nonselectively target LMP7 and other subunits of the constitutive proteasome and immunoproteasome with comparable potency, which can limit the therapeutic applicability of these drugs. Here, we describe the discovery and structure-based hit optimization of novel amido boronic acids, which selectively inhibit LMP7 while sparing all other subunits. The exploitation of structural differences between the proteasome subunits culminated in the identification of the highly potent, exquisitely selective, and orally available LMP7 inhibitor 50 (M3258). Based on the strong antitumor activity observed with M3258 in MM models and a favorable preclinical data package, a phase I clinical trial was initiated in relapsed/refractory MM patients.
- Klein, Markus,Busch, Michael,Friese-Hamim, Manja,Crosignani, Stefano,Fuchss, Thomas,Musil, Djordje,Rohdich, Felix,Sanderson, Michael P.,Seenisamy, Jeyaprakashnarayanan,Walter-Bausch, Gina,Zanelli, Ugo,Hewitt, Philip,Esdar, Christina,Schadt, Oliver
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p. 10230 - 10245
(2021/07/26)
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- Metal-Free Direct Deoxygenative Borylation of Aldehydes and Ketones
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Direct conversion of aldehydes and ketones into alkylboronic esters via deoxygenative borylation represents an unknown yet highly desirable transformation. Herein, we present a one-step and metal-free method for carbonyl deoxy-borylation under mild conditions. A wide range of aromatic aldehydes and ketones are tolerated and successfully converted into the corresponding benzylboronates. By the same deoxygenation manifold with aliphatic aldehydes and ketones, we also enable a concise synthesis of 1,1,2-tris(boronates), a family of compounds that currently lack efficient synthetic methods. Given its simplicity and versatility, we expect that this novel borylation approach could show great promise in organoboron synthesis and inspire more carbonyl deoxygenative transformations in both academic and industrial settings.
- Huang, Chia-Yu,Li, Chao-Jun,Li, Jianbin,Qiu, Zihang,Wang, Haining
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p. 13011 - 13020
(2020/09/01)
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- Regioselective α-benzylation of 3-iodoazetidine via Suzuki cross-coupling
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An efficient protocol for the synthesis of α-benzyl azetidines starting from benzylboronic acid pinacol ester derivatives and 3-iodoazetidine was developed. A wide range of α-benzyl azetidine derivatives were obtained in moderate to good yields with high regioselectivity (>99%).
- Qiu, Zhenjiang,Zhu, Mingxiang,Zheng, Lu,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
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supporting information
p. 1321 - 1324
(2019/04/25)
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- Deaminative Borylation of Aliphatic Amines Enabled by Visible Light Excitation of an Electron Donor–Acceptor Complex
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A deaminative strategy for the borylation of aliphatic primary amines is described. Alkyl radicals derived from the single-electron reduction of redox-active pyridinium salts, which can be isolated or generated in situ, were borylated in a visible light-mediated reaction with bis(catecholato)diboron. No catalyst or further additives were required. The key electron donor–acceptor complex was characterized in detail by both experimental and computational investigations. The synthetic potential of this mild protocol was demonstrated through the late-stage functionalization of natural products and drug molecules.
- Sandfort, Frederik,Strieth-Kalthoff, Felix,Klauck, Felix J. R.,James, Michael J.,Glorius, Frank
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supporting information
p. 17210 - 17214
(2018/11/10)
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- Isoquinolone compound and application thereof
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The invention relates to an isoquinolone compound and application thereof. The invention in particular relates to an isoquinolone compound used as a HIF prolyl hydroxylase inhibitor (HIF-PHI) and a pharmaceutical composition thereof. Moreover, the present invention provides the application of the isoquinolinone compound or the pharmaceutical composition thereof in the preparation of a medicament for preventing or treating HIF-associated or HIF-mediated diseases as anemia or ischemia, local ischemia or hypoxia.
- -
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Paragraph 0445-0448
(2018/09/08)
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- Method for synthesizing alkylborate compound
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The invention discloses a method for synthesizing an alkylborate compound, and concretely relates to a method for synthesizing the alkylborate compound through a cross-coupling reaction of chloralkaneand bis(pinacolato)diboron in the presence of metallic magnesium with Fe(acac)3 (acac = an acetylacetonate group) as a single component catalyst. The method for synthesizing the alkylborate compoundavoids the use of sensitive metal organic solvents and multi-component catalysts, realizes bilateral utilization of the bis(pinacolato)diboron, greatly reduces the use amount of the bis(pinacolato)diboron, and allows the coupling reaction of the cheap and easily-available chloralkane to be smoothly carried out under mild conditions; and compared with methods reported in literatures, the method disclosed in the invention has a better atom economy, a same or higher catalysis efficiency and a wider substrate applicability.
- -
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Paragraph 0026
(2018/05/01)
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- STABILIZATION OF ACTIVE METAL CATALYSTS AT METAL-ORGANIC FRAMEWORK NODES FOR HIGHLY EFFICIENT ORGANIC TRANSFORMATIONS
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Metal-organic framework (MOFs) compositions based on post?synthetic metalation of secondary building unit (SBU) terminal or bridging OH or OH2 groups with metal precursors or other post-synthetic manipulations are described. The MOFs provide a versatile family of recyclable and reusable single-site solid catalysts for catalyzing a variety of asymmetric organic transformations, including the regioselective boryiation and siiylation of benzyiic C—H bonds, the hydrogenation of aikenes, imines, carbonyls, nitroarenes, and heterocycles, hydroboration, hydrophosphination, and cyclization reactions. The solid catalysts can also be integrated into a flow reactor or a supercritical fluid reactor.
- -
-
Paragraph 0238; 0243
(2019/01/07)
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- Synthesis of Benzyl-, Allyl-, and Allenyl-boronates via Copper-Catalyzed Borylation of Alcohols
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Alcohols are among the most abundant and readily available organic feedstocks in industrial processes. The direct catalytic functionalization of sp3 C-O bonds of alcohols remains the main challenge in this field. Here, we report a copper-cataly
- Mao, Lujia,Szabó, Kálmán J.,Marder, Todd B.
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supporting information
p. 1204 - 1207
(2017/03/14)
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- Preparation method of benzyl boron ester compound
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The invention discloses a preparation method of a benzyl boron ester compound. According to the preparation method, aromatic boric acid Ar-B(OH)2, trimethyl silicon-based diazomethane, pinacol and tetrabutyl ammonium fluoride are subjected to a reaction in an organic solvent so as to obtain a benzyl pinacol boron ester compound, wherein Ar represents a non-heterocyclic aromatic group. After the method is adopted, the benzyl boron ester compound is obtained by starting from the aromatic boric acid and converting under a one-pot condition; the method is mild in reaction conditions, the reaction related to the method occurs smoothly in the air without needing strict water-free and oxygen-free conditions, and the method is convenient and simple to operate; the method has better tolerance and universality for functional groups and does not need an expensive metal catalyst and a ligand, thus being lower in reaction cost and being widely used for preparing the benzyl boron ester compound.
- -
-
Paragraph 0076; 0077; 0078; 0079; 0080; 0081
(2017/06/02)
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- Pd-catalyzed cross-coupling of 1,1-diborylalkanes with aryl triflates
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The Pd-catalyzed synthesis of benzylboronic esters through coupling of aryl triflates with 1,1-diborylalkane under ambient conditions is described. Varieties of primary and secondary arylboronic esters could be successfully synthesized by this strategy. C
- Cui, Long-Can,Zhang, Zhen-Qi,Lu, Xi,Xiao, Bin,Fu, Yao
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p. 51932 - 51935
(2016/06/13)
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- High-Turnover Aromatic C-H Borylation Catalyzed by POCOP-Type Pincer Complexes of Iridium
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The catalytic C-H borylation of arenes with HBpin (pin = pinacolate) using POCOP-type pincer complexes of Ir has been demonstrated, with turnover numbers exceeding 10 000 in some cases. The selectivity of C-H activation was based on steric preferences and largely mirrored that found in other Ir borylation catalysts. Catalysis in the (POCOP)Ir system depends on the presence of stoichiometric quantities of sacrificial olefin, which is hydrogenated to consume the H2 equivalents generated in the borylation of C-H bonds with HBpin. Smaller olefins such as ethylene or 1-hexene were more advantageous to catalysis than sterically encumbered tert-butylethylene (TBE). Olefin hydroboration is a competing side reaction. The synthesis and isolation of multiple complexes potentially relevant to catalysis permitted examination of several key elementary reactions. These experiments indicate that the C-H activation step in catalysis ostensibly involves oxidative addition of an aromatic C-H bond to the three-coordinate (POCOP)Ir species. The olefin is mechanistically critical to gain access to this 14-electron, monovalent Ir intermediate. C-H activation at Ir(I) here is in contrast to the olefin-free catalysis with state-of-the-art Ir complexes supported by neutral bidentate ligands, where the C-H activating step is understood to involve trivalent Ir-boryl intermediates.
- Press, Loren P.,Kosanovich, Alex J.,McCulloch, Billy J.,Ozerov, Oleg V.
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supporting information
p. 9487 - 9497
(2016/08/12)
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- Iridium-Catalyzed Borylation of Primary Benzylic C-H Bonds without a Directing Group: Scope, Mechanism, and Origins of Selectivity
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Primary benzylic boronate esters are useful intermediates in organic synthesis, but these reagents cannot be prepared by hydroboration. The benzylic C-H borylation of methylarenes would be a method to form these products, but such reactions without neat methylarene or a directing group are unknown. We report an approach to divert the borylation of methylarenes from aromatic positions to benzylic positions with a silylborane as reagent and a new iridium catalyst containing an electron-deficient phenanthroline as ligand. This system forms benzylic boronate esters selectively over the corresponding aryl boronate esters. An Ir diboryl monosilyl complex ligated by the phenanthroline was isolated and determined to be the resting state of the catalyst. Mechanistic studies show that this complex is kinetically competent to be an intermediate in the catalytic process. Kinetic studies of benzylic and aryl C-H borylation catalyzed by various Ir complexes show that the rate of aryl C-H borylation decreases with decreasing electron density at the metal center of the Ir catalyst, but that the rate of benzylic C-H borylation is less sensitive to the degree of electron density at the metal center of the Ir catalyst. Kinetic and computational studies suggest that the two borylation reactions respond differently to the degree of electron density at the metal center because they occur with different turnover-limiting steps. The turnover-limiting step in the borylation of aryl C-H bonds is known to be C-H oxidative addition, but the turnover-limiting step of the borylation of benzylic C-H bonds appears to be an isomerization prior to C-B reductive elimination.
- Larsen, Matthew A.,Wilson, Conner V.,Hartwig, John F.
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p. 8633 - 8643
(2015/07/15)
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- Iron-catalyzed borylation of alkyl electrophiles
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The use of low-cost iron(III) acetoacetate (Fe(acac)3) and tetramethylethylenediamine (TMEDA) enables the direct cross-coupling of alkyl halides with bis(pinacolato)diboron. This approach allows for the borylation of activated or unactivated primary, secondary, and tertiary bromides. Moreover, even the borylation of benzylic or allylic chlorides, tosylates, and mesylates are possible. The reactions proceed under mild conditions at room temperature and show broad functional-group compatibility and "robustness" as measured by a modified Glorius robustness screen.
- Atack, Thomas C.,Lecker, Rachel M.,Cook, Silas P.
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supporting information
p. 9521 - 9523
(2014/07/22)
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- Palladium nanoparticle catalysis: Borylation of aryl and benzyl halides and one-pot biaryl synthesis via sequential borylation-Suzuki-Miyaura coupling
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Palladium nanoparticles generated in PEG catalyze the reaction of bis(pinacolato)diboron with various aryl/benzyl halides to afford aryl/benzyl boronates in high yield. Arylboronates thus prepared, have been directly used in the Suzuki-Miyaura coupling reaction with different aryl halides and benzyl halides in a convenient one-pot, two-step solvent free green synthesis of unsymmetrical biaryls and diarylmethanes. The Royal Society of Chemistry 2012.
- Bej, Ansuman,Srimani, Dipankar,Sarkar, Amitabha
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experimental part
p. 661 - 667
(2012/05/04)
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- Transition-metal-free synthesis of pinacol alkylboronates from tosylhydrazones
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Highly efficient: Pinacol alkylboronates were synthesized by the reaction of tosylhydrazones with bis(pinacolato)diboron or pinacolborane under transition-metal-free conditions. This reaction represents an expeditious conversion of carbonyl functionality into a boronate group. Copyright
- Li, Huan,Wang, Long,Zhang, Yan,Wang, Jianbo
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p. 2943 - 2946
(2012/04/18)
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- Nickel-catalyzed coupling reactions of alkyl electrophiles, including unactivated tertiary halides, to generate carbon-boron bonds
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Through the use of a catalyst formed in situ from NiBr2? diglyme and a pybox ligand (both of which are commercially available), we have achieved our first examples of coupling reactions of unactivated tertiary alkyl electrophiles, as well as our first success with nickel-catalyzed couplings that generate bonds other than C-C bonds. Specifically, we have determined that this catalyst accomplishes Miyaura-type borylations of unactivated tertiary, secondary, and primary alkyl halides with diboron reagents to furnish alkylboronates, a family of compounds with substantial (and expanding) utility, under mild conditions; indeed, the umpolung borylation of a tertiary alkyl bromide can be achieved at a temperature as low as -10 °C. The method exhibits good functional-group compatibility and is regiospecific, both of which can be issues with traditional approaches to the synthesis of alkylboronates. In contrast to seemingly related nickel-catalyzed C-C bond-forming processes, tertiary halides are more reactive than secondary or primary halides in this nickel-catalyzed C-B bond-forming reaction; this divergence is particularly noteworthy in view of the likelihood that both transformations follow an inner-sphere electron-transfer pathway for oxidative addition.
- Dudnik, Alexander S.,Fu, Gregory C.
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p. 10693 - 10697
(2012/08/08)
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- Alkylboronic esters from copper-catalyzed borylation of primary and secondary alkyl halides and pseudohalides
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Easy access: An unprecedented copper-catalyzed cross-coupling reaction of the title compounds with diboron reagents is described (see scheme; Ts=4-toluenesulfonyl). This reaction can be used to prepare both primary and secondary alkylboronic esters having diverse structures and functional groups. The resulting products would be difficult to access by other means. Copyright
- Yang, Chu-Ting,Zhang, Zhen-Qi,Tajuddin, Hazmi,Wu, Chen-Cheng,Liang, Jun,Liu, Jing-Hui,Fu, Yao,Czyzewska, Maria,Steel, Patrick G.,Marder, Todd B.,Liu, Lei
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supporting information; experimental part
p. 528 - 532
(2012/02/04)
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- PROCESS FOR PREPARING BORONIC ACIDS AND ESTERS IN THE PRESENCE OF MAGNESIUM METAL
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The present invention relates to the process for preparing a boronic acid or ester chemically, in which an aromatic compound is reacted with a boronating agent, in the presence of magnesium metal (Mg0). The invention also relates to the boronic acids or esters that can be obtained by means of this process and to the use thereof for example as a synthesis intermediate, in the Suzuki reaction, in the pharmaceutical or alternatively electronics field.
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Page/Page column 8
(2011/11/30)
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- An opportunity for Mg-catalyzed grignard-type reactions: Direct coupling of benzylic halides with pinacolborane with 10 mol % of magnesium
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Mg in catalytic amounts as the only metal permits the reductive coupling between benzyl halides and pinacolborane. HBpin acts both as an electrophile and as a reducing agent to regenerate an organomagnesium species in situ. An hydride oxidation mechanism is proposed on the basis of DFT calculations.
- Pintaric, Christine,Olivero, Sandra,Gimbert, Yves,Chavant, Pierre Y.,Dunach, Elisabet
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supporting information; experimental part
p. 11825 - 11827
(2010/11/02)
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- Iridium-catalyzed preparation of silylboranes by silane borylation and their use in the catalytic borylation of arenes
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Silylboranes are versatile reagents for transition metal-catalyzed reactions of unsaturated organic molecules. These reagents are typically prepared by the addition of a silyl lithium species to a boron electrophile. However, the need to generate anionic silane reagents limits the scope of silylboranes that can be readily obtained. Here, we describe the synthesis of trialkylsilylboranes by the borylation of silanes catalyzed by iridium complexes. The reaction of trialkylhydrosilanes with B2pin 2 catalyzed by the combination of [Ir(OMe)cod]2 and 4,4′-di-tert-butylbipyridine forms trialkylsilylboronic esters. In addition, we show that these trialkylsilylboranes serve as boron sources for the iridium-catalyzed borylation of aryl C-H bonds. In contrast to diboron reagents, the silylboranes react with methylarenes at both the aryl and methyl C-H bonds.
- Boebel, Timothy A.,Hartwig, John F.
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p. 6013 - 6019
(2009/04/13)
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- Synthesis of benzylic boronates via palladium-catalyzed cross-coupling reaction of bis(pinacolato)diboron with benzylic halides
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The palladium cross-coupling reaction of benzyl halides with diboron 1 yielded structurally diverse pinacol benzylic boronates. Under these reaction conditions, sensitive functionalities such as esters and nitriles are tolerated and the benzylic boronates
- Giroux, André
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p. 233 - 235
(2007/10/03)
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- Nucleophilic borylation of benzyl halides with bis(pinacolato)diboron catalyzed by palladium(0) complexes
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Nucleophilic borylation of benzyl halides with bis(pinacolato)diboron in the presence of KOAc in toluene was effectively catalyzed by a palladium complex generated in situ from Pd(dba)2 and (4-MeOC6H4)3P, giving the corresponding pinacol benzylboronates in high yields.
- Ishiyama, Tatsuo,Oohashi, Zengo,Ahiko, Taka-Aki,Miyaura, Norio
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p. 780 - 781
(2007/10/03)
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