24388-23-6Relevant articles and documents
Evaluation of Cobalt Complexes Bearing Tridentate Pincer Ligands for Catalytic C-H Borylation
Schaefer, Brian A.,Margulieux, Grant W.,Small, Brooke L.,Chirik, Paul J.
, p. 1307 - 1320 (2015)
Cobalt(II) dichloride complexes supported by a variety of neutral, tridentate pincer ligands have been prepared and, following in situ activation with NaBEt3H, evaluated for the catalytic borylation of 2-methylfuran, 2,6-lutidine, and benzene using both HBPin and B2Pin2 (Pin = pinacolate) as boron sources. Preparation of well-defined organometallic compounds in combination with stoichiometric experiments with HBPin and B2Pin2 provided insight into the nature and kinetic stability of the catalytically relevant species. In cases where sufficiently electron donating pincers are present, such as with bis(phosphino)pyridine chelates, Co(III) resting states are preferred and catalytic C-H borylation is efficient. Introduction of a redox-active subunit into the pincer reduces its donating ability and, as a consequence, the accessibility of a Co(III) resting state. In these cases, unusual mixed-valent μ-hydride cobalt complexes have been crystallographically and spectroscopically characterized. These studies have also shed light on the active species formed during in situ activated cobalt alkene hydroboration catalysis and provide important design criteria in base metal catalyzed C-B bond forming reactions. (Chemical Presented).
Application of a nucleophilic boryl complex in the frustrated Lewis pair: Activation of H-H, B-H and CC bonds with B(C6F5)3 and boryl-borate lithium
Zheng, Junhao,Wang, Yuwen,Li, Zhen Hua,Wang, Huadong
, p. 5505 - 5508 (2015)
The frustrated Lewis pair comprised of B(C6F5)3 and a boryl-borate lithium salt Li[pinBB(Ph)pin] can efficiently activate dihydrogen, pinacolborane and ethylene at ambient temperature. Theoretical studies suggest that the nucleophilic sp2 boryl moiety of Li[pinBB(Ph)pin] plays different roles in these reactions. This journal is
Paper-Based Colorimetric Sensor System for High-Throughput Screening of C?H Borylation
Kim, Han-Sung,Eom, Min Sik,Han, Min Su,Lee, Sunwoo
, p. 6282 - 6285 (2017)
A paper-based colorimetric sensor system (PBCSS) was developed to detect the amount of bis(pinacolato)diboron (B2Pin2) and applied as a high-throughput screening protocol in Ir-catalyzed C?H borylation. First, 96 ligands were screened for the borylation of benzene, and then 12 of them were selected and tested for five substrates. These reaction mixtures were spotted in the PBCSS, showing a blue-violet color. The value of the gray scale of each reaction was obtained from these colored spots and converted to the extent of conversion of B2Pin2. The extents of conversion of B2Pin2 obtained from the PBCSS showed good correlation with those obtained from gas chromatography analysis. In addition, the modified conversion using blank data showed good correlation with the yield of products.
Aromatic C-H borylation catalyzed by iridium/2,6-diisopropyl-N-(2- pyridylmethylene)aniline complex
Tagata, Tsuyosi,Nishida, Mayumi
, p. 1655 - 1660 (2004)
The C-H borylation of aromatic and heteroaromatic compounds, such as benzene, 1,3-dichlorobenzene, 1,3-bis(trifluoromethyl)benzene, 2,6-dichloropyridine, indole, benzothiophene and benzofuran, by bis(pinacolato)diboron or pinacolborane was catalyzed by a 1/2 [IrCl(COD)] 2-2,6-diisopropyl-N-(2-pyridylmethylene)aniline complex. The isopropyl groups of the ligand are essential for obtaining the products in high yield. Octane was a suitable solvent for the reactions of the above compounds except for indole. In the case of indole, DME was better than octane and the yield tended to improve with a smaller amount of the catalyst.
Photochemical and electrochemical C-N borylation of arylhydrazines
Du, Linlin,Sun, Li,Zhang, Hua
supporting information, p. 1716 - 1719 (2022/02/21)
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
Mono-Phosphine Metal-Organic Framework-Supported Cobalt Catalyst for Efficient Borylation Reactions
Akhtar, Naved,Antil, Neha,Balendra,Begum, Wahida,Chauhan, Manav,Gupta, Poorvi,Kumar, Ajay,Malik, Jaideep,Manna, Kuntal,Newar, Rajashree
supporting information, (2022/03/15)
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.
