25015-63-8Relevant articles and documents
Ruthenium-catalyzed regiospecific borylation of methyl C-H bonds
Murphy, Jaclyn M.,Lawrence, Joshua D.,Kawamura, Kazumori,Incarvito, Christopher,Hartwig, John F.
, p. 13684 - 13685 (2006)
We report the regiospecific, ruthenium-catalyzed borylation of saturated terminal C-H bonds. Alkylboronates were obtained in 78-98% yields. The borylations of alkanes, trialkylamines, protected alcohols, and fluoroalkanes occurred regiospecifically at the methyl group that is least sterically hindered. In contrast to most organometallic C-H activation, the reactions of alkanes occurred in higher yields than the reactions of arenes. Reactions were conducted that probed steric and electronic effects on the alkyl borylation. These reactions showed that the borylation occurred preferentially at the methyl group that is least sterically hindered and most electron-deficient. Ruthenium compounds containing boryl ligands were synthesized, and one was characterized by X-ray crystallography. One of these compounds contained a rare bridging boryl ligand and served as a catalyst precursor for the borylation of octane. Copyright
Metal-Organic Framework Stabilizes a Low-Coordinate Iridium Complex for Catalytic Methane Borylation
Feng, Xuanyu,Song, Yang,Li, Zhe,Kaufmann, Michael,Pi, Yunhong,Chen, Justin S.,Xu, Ziwan,Li, Zhong,Wang, Cheng,Lin, Wenbin
, p. 11196 - 11203 (2019)
Catalytic borylation has recently been suggested as a potential strategy to convert abundant methane to fine chemicals. However, synthetic utility of methane borylation necessitates significant improvement of catalytic activities over original phenanthroline-and diphosphine-Ir complexes. Herein, we report the use of metal-organic frameworks (MOFs) to stabilize low-coordinate Ir complexes for highly active methane borylation to afford the monoborylated product. The mono(phosphine)-Ir based MOF, Zr-P1-Ir, significantly outperformed other Ir catalysts in methane borylation to afford CH3Bpin with a turnover number of 127 at 110 °C. Density functional theory calculations indicated a significant reduction of activation barrier for the rate limiting oxidative addition of methane to the four-coordinate (P1)IrIII(Bpin)3 catalyst to form the six-coordinate (P1)IrV(Bpin)3(CH3)(H) intermediate, thus avoiding the formation of sterically encumbered seven-coordinate IrV intermediates as found in other Ir catalysts based on chelating phenanthroline, bipyridine, and diphosphine ligands. MOF thus stabilizes the homogeneously inaccessible, low-coordinate (P1)Ir(boryl)3 catalyst to provide a unique strategy to significantly lower the activation barrier for methane borylation. This MOF-based catalyst design holds promise in addressing challenging catalytic reactions involving highly inert substrates.
Hydrogen Evolution from Telescoped Miyaura Borylation and Suzuki Couplings Utilizing Diboron Reagents: Process Safety and Hazard Considerations
Borkar, Indrakant,Brewer, Alison Campbell,Buser, Jonas Y.,Campos, Odilon,Fleming, Jeffrey,Forst, Mindy B.,Hansen, Caoimhe,Humenik, Ashley,Jeffery, Stephen,Kokitkar, Prashant B.,Kolis, Stanley P.,Lambertus, Gordon R.,Martinelli, Joseph R.,McCartan, Ciaran,Merritt, Jeremy M.,Moursy, Hossam,Murphy, Donal,Murray, Michael M.,O'Donnell, Kevin,O'Sullivan, Rita,Richardson, Gary A.,Xia, Han
, (2021/08/30)
The hazard assessment of a telescoped Miyaura borylation and Suzuki coupling reaction employing bis(pinacolato)diboron (BisPin), used in the developmental synthesis of an intermediate for abemaciclib, led to the observation of hydrogen being generated. Quantitative headspace GC and solution 11B NMR were used to show that the rapid decomposition of the excess BisPin from the borylation under the aqueous basic conditions of the Suzuki reaction was responsible for H2 generation. The moles of H2 observed were found equal to the BisPin excess, which is rationalized by mass balance and a stoichiometric reaction. The possible generation of the stoichiometric levels of H2 should be considered in hazard assessments of this class of reaction. Kinetic and process modeling was used to minimize the risk upon scale-up, and results for commercial manufacturing batches are presented, which showed good agreement with the lab scale data. Furthermore, the hydrogen evolution potentials of other common borylating agents including bisboronic acid (BBA) and pinacol borane were demonstrated.
Synthesis of DBpin using Earth-abundant metal catalysis
Cummins, Andrew W. M.,Docherty, Jamie H.,Li, Shuyang,Muilu, Tommi,Thomas, Stephen P.,Willcox, Dominic R.
supporting information, (2020/03/10)
The synthesis of DBpin was achieved using (EtBIP)CoCl2 or (tBuPNN)FeCl2 as pre-catalysts activated with NaOtBu. (EtBIP)CoCl2 was used as a pre-catalyst for the hydrogen isotope exchange of HBpin with D2, and (tBuPNN)FeCl2 for deuterogenolysis of B2pin2. The one-pot, tandem hydrogenolysis-hydroboration/deuterogenolysis-deuteroboration reaction of terminal alkenes could be catalysed by (tBuPNN)FeCl2 to give alkyl boronic esters.