- Does Lewis basicity correlate with catalytic performance in zerovalent group 8 complexes?
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A set of 18 zerovalent group 8 metal complexes of the form [MLn(CO)5-n] (M=Fe, Ru, Os; L=neutral donor; n=0-2) were screened for their catalytic performance in aldehyde hydrosilylation and olefin hydroboration reactions. Although none of the untested catalysts were found to perform better than the previously-published complex [Fe(CO)4(IMes)] (IMes=1,3-Dimesityliidazol-2-ylidene), the results suggest that the Lewis basicity of the metal complex does not play a critical role in the catalysis of these two reactions.
- Braunschweig, Holger,Brunecker, Carina,Dewhurst, Rian D.,Schneider, Christoph
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Read Online
- Transition metal- And light-free radical borylation of alkyl bromides and iodides using silane
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We report operationally simple and neutral conditions for borylation of alkyl bromides and iodides to alkyl boronic esters under transition metal- and light-free conditions. A series of substrates with a wide range of functional groups were effectively transformed into the borylation products in moderate to good yields. Mechanistic studies, including radical clock experiments and DFT calculations, gave detailed insight into the radical borylation process.
- Mo, Fanyang,Sun, Beiqi,Zheng, Sihan
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supporting information
p. 5674 - 5677
(2021/06/16)
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- Ruthenium-Catalyzed Dehydrogenation Through an Intermolecular Hydrogen Atom Transfer Mechanism
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The direct dehydrogenation of alkanes is among the most efficient ways to access valuable alkene products. Although several catalysts have been designed to promote this transformation, they have unfortunately found limited applications in fine chemical synthesis. Here, we report a conceptually novel strategy for the catalytic, intermolecular dehydrogenation of alkanes using a ruthenium catalyst. The combination of a redox-active ligand and a sterically hindered aryl radical intermediate has unleashed this novel strategy. Importantly, mechanistic investigations have been performed to provide a conceptual framework for the further development of this new catalytic dehydrogenation system.
- Huang, Lin,Bismuto, Alessandro,Rath, Simon A.,Trapp, Nils,Morandi, Bill
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supporting information
p. 7290 - 7296
(2021/03/01)
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- Hydroboration of Terminal Alkenes and trans-1,2-Diboration of Terminal Alkynes Catalyzed by a Manganese(I) Alkyl Complex
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A MnI-catalyzed hydroboration of terminal alkenes and a 1,2-diboration of terminal alkynes with pinacolborane (HBPin) is described. For alkenes, anti-Markovnikov hydroboration takes place; for alkynes the reaction proceeds with excellent trans-1,2-selectivity. The most active pre-catalyst is bench-stable alkyl bisphosphine MnI complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)]. The catalytic process is initiated by migratory insertion of a CO ligand into the Mn–alkyl bond to yield an acyl intermediate, which undergoes B?H bond cleavage of HBPin (for alkenes) and rapid C?H bond cleavage (for alkynes), forming the active MnI boryl and acetylide catalysts [Mn(dippe)(CO)2(BPin)] and [Mn(dippe)(CO)2(C≡CR)], respectively. A broad variety of aromatic and aliphatic alkenes and alkynes was efficiently and selectively borylated. Mechanistic insights are provided based on experimental data and DFT calculations revealing that an acceptorless reaction is operating involving dihydrogen release.
- Kirchner, Karl,St?ger, Berthold,Veiros, Luis F.,Weber, Stefan,Zobernig, Daniel
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supporting information
p. 24488 - 24492
(2021/10/19)
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- Synthesis and Catalytic Reactivity of Cobalt Pincer Nitrosyl Hydride Complexes
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The synthesis, characterization, and catalytic activity of low-spin {CoNO}8 pincer complexes of the type [Co(PCP)(NO)(H)] are described. These compounds are obtained either by reacting [Co(PCP)(κ2-BH4)] with NO and Et3N or, alternatively, by reacting [Co(
- Pecak, Jan,Fleissner, Sarah,Veiros, Luis F.,Pittenauer, Ernst,St?ger, Berthold,Kirchner, Karl
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p. 278 - 285
(2021/02/03)
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- Visible-light-mediated borylation of aryl and alkyl halides with a palladium complex
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Palladium catalyzed visible-light-mediated borylation of inactivated aryl and alkyl halides is reported; the method provided high yields and excellent functional group compatibility. Furthermore, arylsilicates were synthesized selectively using dimethylphenylsilyl boronic ester via changing the reaction conditions. Finally, the possible reaction mechanism is determined through fluorescence quenching and turn on/off experiments.
- Zhao, Jia-Hui,Zhou, Zhao-Zhao,Zhang, Yue,Su, Xuan,Chen, Xi-Meng,Liang, Yong-Min
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supporting information
p. 4390 - 4394
(2020/10/20)
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- Diverse functionalization of strong alkyl C–H bonds by undirected borylation
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The selective functionalization of strong, typically inert carbon-hydrogen (C–H) bonds in organic molecules is changing synthetic chemistry. However, the undirected functionalization of primary C–H bonds without competing functionalization of secondary C–H bonds is rare. The borylation of alkyl C–H bonds has occurred previously with this selectivity, but slow rates required the substrate to be the solvent or in large excess. We report an iridium catalyst ligated by 2-methylphenanthroline with activity that enables, with the substrate as limiting reagent, undirected borylation of primary C–H bonds and, when primary C–H bonds are absent or blocked, borylation of strong secondary C–H bonds. Reactions at the resulting carbon-boron bond show how these borylations can lead to the installation of a wide range of carbon-carbon and carbon-heteroatom bonds at previously inaccessible positions of organic molecules.
- Oeschger, Raphael,Su, Bo,Yu, Isaac,Ehinger, Christian,Romero, Erik,He, Sam,Hartwig, John
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p. 736 - 741
(2020/06/27)
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- Alkyl-halide boron esterification reaction method free from transition metal catalysis
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The invention discloses an alkyl-halide boron esterification reaction method free from transition metal catalysis. The method has the advantages that the transition metal catalysis is not needed, boric acid ester serves as a boron source, alkoxide serves
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Paragraph 0041; 0042
(2019/04/17)
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- Transition-Metal-Free Borylation of Alkyl Iodides via a Radical Mechanism
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We describe an operationally simple transition-metal-free borylation of alkyl iodides. This method uses commercially available diboron reagents as the boron source and exhibits excellent functional group compatibility. Furthermore, a diverse range of prim
- Liu, Qianyi,Hong, Junting,Sun, Beiqi,Bai, Guangcan,Li, Feng,Liu, Guoquan,Yang, Yang,Mo, Fanyang
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supporting information
(2019/07/08)
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- Photoinduced Deaminative Borylation of Alkylamines
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An operationally simple deaminative borylation reaction of primary alkylamines has been developed. The formation of electron-donor-acceptor complexes between N-alkylpyridinium salts and bis(catecholato)diboron enables photoinduced single-electron transfer and fragmentation to carbon-centered radicals, which are subsequently borylated. The mild conditions allow a diverse range of readily available alkylamines to be efficiently converted into synthetically valuable alkylboronic esters under catalyst-free conditions.
- Wu, Jingjing,He, Lin,Noble, Adam,Aggarwal, Varinder K.
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supporting information
p. 10700 - 10704
(2018/09/06)
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- Rhodium-catalyzed dehydrogenative borylation of aliphatic terminal alkenes with pinacolborane
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Aliphatic terminal alkenes react with pinacolborane at ambient temperature to afford dehydrogenative borylation compounds as the major product when iPr-Foxap is used as the ligand with cationic rhodium(I) in the presence of norbornene, which acts as the s
- Morimoto, Masao,Miura, Tomoya,Murakami, Masahiro
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supporting information
p. 12659 - 12663
(2015/10/28)
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- Rh(I)-catalyzed borylation of primary alkyl chlorides
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Rhodium-catalyzed cross-coupling reactions of unactivated primary alkyl chlorides with diboron reagents have been developed as practical methods for the synthesis of alkylboronic esters. These reactions expand the concept and utility of Rh(I)-catalyzed cr
- Gong, Tian-Jun,Jiang, Yuan-Ye,Fu, Yao
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p. 397 - 400
(2014/03/21)
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- FLUORESCENCE DETECTION OF POISON OAK OIL
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The invention herein disclosed provides for compositions, methods for synthesizing said compositions, and methods for using said compositions, wherein the compositions and methods may be used to bind to and/or deactivate a poison oak oil, such as urushiol. The compositions and methods can be used to treat and/or reduce an inflammatory reaction and/or hypersensitivity to natural compounds found in poison oak, poison ivy, poison sumac, mango, lac tree, and cashew nut.
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Paragraph 0060; 0092
(2013/05/22)
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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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