- 1,2-Arylboration of aliphatic alkenes by cooperative palladium/copper catalysis
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A method for the 1,2-arylboration of aliphatic alkenes to afford alkylboronic esters by cooperative palladium/copper catalysis was developed. The reaction proceeds in a highly regioselective manner, and various functional groups such as silyl ether, alkoxycarbonyl, and cyano groups are tolerated under the applied reaction conditions.
- Semba, Kazuhiko,Ohtagaki, Yasuhiro,Nakao, Yoshiaki
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- Defunctionalization of sp3 C–Heteroatom and sp3 C–C Bonds Enabled by Photoexcited Triplet Ketone Catalysts
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A general strategy for enabling a light-induced defunctionalization of sp3 C–heteroatom and sp3 C–C bonds with triplet ketone catalysts and bipyridine additives is disclosed. This protocol is characterized by its broad scope without recourse to transition metal catalysts or stoichiometric exogeneous reductants, thus offering a complementary technique for activating σ sp3 C–C(heteroatom) bonds. Preliminary mechanistic studies suggest that the presence of 2,2′-bipyridines improves the lifetime of ketyl radical intermediates.
- An, Juzeng,Gu, Yiting,Martin, Ruben,Wakeling, Matthew,Yin, Hongfei
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p. 1031 - 1036
(2022/01/19)
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- Silver-Catalyzed Hydroboration of C-X (X = C, O, N) Multiple Bonds
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AgSbF6 was developed as an effective catalyst for the hydroboration of various unsaturated functionalities (nitriles, alkenes, and aldehydes). This atom-economic chemoselective protocol works effectively under low catalyst loading, base- A nd solvent-free moderate conditions. Importantly, this process shows excellent functional group tolerance and compatibility with structurally and electronically diverse substrates (>50 examples). Mechanistic investigations revealed that the reaction proceeds via a radical pathway. Further, the obtained N,N-diborylamines were showcased to be useful precursors for amide synthesis.
- Pandey, Vipin K.,Tiwari, Chandra Shekhar,Rit, Arnab
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supporting information
p. 1681 - 1686
(2021/03/03)
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- Electrochemical Borylation of Alkyl Halides: Fast, Scalable Access to Alkyl Boronic Esters
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Herein, a fast, scalable, and transition-metal-free borylation of alkyl halides (X = I, Br, Cl) enabled by electroreduction is reported. This process provides an efficient and practical access to primary, secondary, and tertiary boronic esters at a high current. More than 70 examples, including the late-stage borylation of natural products and drug derivatives, are furnished at room temperature, thereby demonstrating the broad utility and functional-group tolerance of this protocol. Mechanistic studies disclosed that B2cat2 serves as both a reagent and a cathodic mediator, enabling electroreduction of difficult-to-reduce alkyl bromides or chlorides at a low potential.
- Wang, Bingbing,Peng, Pan,Ma, Wan,Liu, Zhao,Huang, Cheng,Cao, Yangmin,Hu, Ping,Qi, Xiaotian,Lu, Qingquan
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supporting information
p. 12985 - 12991
(2021/09/03)
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- Metal-organic frameworks containing nitrogen-donor ligands for efficient catalytic organic transformations
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Metal-organic framework (MOFs) compositions based on nitrogen donor-based organic bridging ligands, including ligands based on 1,3-diketimine (NacNac), bipyridines and salicylaldimine, were synthesized and then post-synthetically metalated with metal precursors, such as complexes of first row transition metals. Metal complexes of the organic bridging ligands could also be directly incorporated into the MOFs. The MOFs provide a versatile family of recyclable and reusable single-site solid catalysts for catalyzing a variety of asymmetric organic transformations. The solid catalysts can also be integrated into a flow reactor or a supercritical fluid reactor.
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Page/Page column 49-50
(2020/06/03)
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- OPTICALLY ACTIVE 2,3-BISPHOSPHINOPYRAZINE DERIVATIVE, METHOD FOR PRODUCING SAME, TRANSITION METAL COMPLEX, AND METHOD FOR PRODUCING ORGANIC BORON COMPOUND
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An optically active 2,3-bisphosphinopyrazine derivative represented by the following general formula (1): wherein R1 represents a group selected from a branched alkyl group having 3 or more carbon atoms, an adamantyl group, an optionally substi
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Paragraph 0210-0212; 0215
(2020/12/13)
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- Alkene hydroboration with pinacolborane catalysed by lithium diisobutyl-: Tert-butoxyaluminum hydride
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Here we developed a highly efficient alkene hydroboration protocol, showing that various alkyl boronates can be smoothly obtained in good yields by reacting alkenes with pinacolborane (HBpin) in the presence of 5 mol% lithium diisobutyl-tert-butoxyaluminum hydride. The coordination of aluminate ions with lithium cations allowed for effective hydride transfer during hydroboration, and the obtained boronate ester was further used for C-C coupling, trifluoroboronate salt formation, and oxidation to alcohol.
- Jaladi, Ashok Kumar,Shin, Won Kyu,An, Duk Keun
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p. 26483 - 26486
(2019/09/12)
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- Ni-catalyzed hydroboration and hydrosilylation of olefins with diboron and silylborane
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Herein we report a Ni-catalyzed formal hydroboration of olefins, which afforded anti-Markovnikov-type alkylboranes with B2pin2 and a stoichiometric amount of water. Formal hydrosilylation using air- and moisture-sensitive silylborane
- Kamei, Toshiyuki,Nishino, Sohshi,Shimada, Toyoshi
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supporting information
p. 2896 - 2899
(2018/06/18)
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- Ruthenium-Catalyzed Anti-Markovnikov Selective Hydroboration of Olefins
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Ruthenium-catalyzed selective hydroboration of styrenes and aliphatic olefins with pinacolborane (HBpin) is reported. This efficient transformation provided products with exclusive anti-Markovnikov selectivity, and this hydroboration protocol is compatible with olefins having electronic and steric divergence as well as diverse functional groups. Hydroboration occurred at room temperature under solvent-free conditions with minimal catalyst load (0.05 mol %) and provided high TON (>1980; >990 per Ru). Mechanistic studies confirmed the involvement of intermediate [{(η6-p-cymene)RuCl}2(μ-H-μ-Cl)] (2). A catalytic cycle including a mononuclear ruthenium intermediate is proposed. The rationale for observed anti-Markovnikov selectivity is provided from reversible 1,3-hydride transfer leading to the regioselective 1,2-insertion on olefins.
- Kisan, Sesha,Krishnakumar, Varadhan,Gunanathan, Chidambaram
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p. 5950 - 5954
(2017/09/15)
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- Highly selective Markovnikov hydroboration of alkyl-substituted terminal alkenes with a phosphine-copper(i) catalyst
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A new method has been developed for the Markovnikov hydroboration of alkyl-substituted terminal alkenes. Notably, the use of a bulky bisphosphine-copper(i) catalyst system resulted in high regioselectivity to afford secondary alkylboronates from the corresponding terminal alkenes (branch/linear = 92 : 8-97 : 3). This method also exhibited good functional group compatibility.
- Iwamoto, Hiroaki,Kubota, Koji,Ito, Hajime
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supporting information
p. 5916 - 5919
(2016/05/24)
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- Conversion of alkanes to linear alkylsilanes using an iridium-iron-catalysed tandem dehydrogenation-isomerization-hydrosilylation
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The conversion of inexpensive, saturated hydrocarbon feedstocks into value-added speciality chemicals using regiospecific, catalytic functionalization of alkanes is a major goal of organometallic chemistry. Linear alkylsilanes represent one such speciality chemical - they have a wide range of applications, including release coatings, silicone rubbers and moulding products. Direct, selective, functionalization of alkanes at primary C-H bonds is difficult and, to date, methods for catalytically converting alkanes into linear alkylsilanes are unknown. Here, we report a well-defined, dual-catalyst system for one-pot, two-step alkane silylations. The system comprises a pincer-ligated Ir catalyst for alkane dehydrogenation and an Fe catalyst that effects a subsequent tandem olefin isomerization-hydrosilylation. This method exhibits exclusive regioselectivity for the production of terminally functionalized alkylsilanes. This dual-catalyst strategy has also been applied to regioselective alkane borylations to form linear alkylboronate esters.
- Jia, Xiangqing,Huang, Zheng
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p. 157 - 161
(2016/02/03)
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- Metal-Organic Frameworks Stabilize Solution-Inaccessible Cobalt Catalysts for Highly Efficient Broad-Scope Organic Transformations
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New and active earth-abundant metal catalysts are critically needed to replace precious metal-based catalysts for sustainable production of commodity and fine chemicals. We report here the design of highly robust, active, and reusable cobalt-bipyridine- and cobalt-phenanthroline-based metal-organic framework (MOF) catalysts for alkene hydrogenation and hydroboration, aldehyde/ketone hydroboration, and arene C-H borylation. In alkene hydrogenation, the MOF catalysts tolerated a variety of functional groups and displayed unprecedentedly high turnover numbers of ~2.5 × 106 and turnover frequencies of ~1.1 × 105 h-1. Structural, computational, and spectroscopic studies show that site isolation of the highly reactive (bpy)Co(THF)2 species in the MOFs prevents intermolecular deactivation and stabilizes solution-inaccessible catalysts for broad-scope organic transformations. Computational, spectroscopic, and kinetic evidence further support a hitherto unknown (bpy?-)CoI(THF)2 ground state that coordinates to alkene and dihydrogen and then undergoing σ-complex-assisted metathesis to form (bpy)Co(alkyl)(H). Reductive elimination of alkane followed by alkene binding completes the catalytic cycle. MOFs thus provide a novel platform for discovering new base-metal molecular catalysts and exhibit enormous potential in sustainable chemical catalysis.
- Zhang, Teng,Manna, Kuntal,Lin, Wenbin
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supporting information
p. 3241 - 3249
(2016/03/19)
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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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- [(NHC)Fe(CO)4]Efficient pre-catalyst for selective hydroboration of alkenes
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[(IMes)Fe(CO)4] [IMes=1,3-bis(2,4,6-trimethylphenyl) imidazol-2-ylidene] complex was found to be an efficient pre-catalyst for the hydroboration of functional alkenes in the presence of pinacolborane at room temperature. Notably, UV irradiation
- Zheng, Jianxia,Sortais, Jean-Baptiste,Darcel, Christophe
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p. 763 - 766
(2014/03/21)
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- Formation of pinacol boronate esters via pyridine iodoborane hydroboration
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(Chemical Equation Presented) Hydroboration of alkenes with pyridine iodoborane followed by treatment with pinacol/NaOH affords monoalkyl pinacol boronates in moderate to good yield. Dialkylborinic acid derivatives are formed competitively, especially in
- Karatjas, Andrew G.,Vedejs, Edwin
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experimental part
p. 9508 - 9510
(2009/04/06)
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