1075719-87-7Relevant academic research and scientific papers
A new enabling technology for convenient laboratory scale continuous flow processing at low temperatures
Browne, Duncan L.,Baumann, Marcus,Harji, Bashir H.,Baxendale, Ian R.,Ley, Steven V.
, p. 3312 - 3315 (2011)
A new machine for conducting continuous flow processes at low temperatures on a laboratory scale is reported. The use of this cryogenic flow reactor has been demonstrated by the preparation of a variety of (hetero)aromatic boronic acids and esters via lit
Preparation and reactions of 4-iodobutyl pinacolborate. Synthesis of substituted alkyl and aryl pinacolboronates via 4-iodobutyl pinacolborate utilizing tetrahydrofuran as the leaving group
Murphy, Chris L.,Hall, Aaron,Roberts, Emily J.,Ryan, Matthew D.,Clary, Jacob W.,Singaram, Bakthan
, p. 3032 - 3033 (2015)
Iodine reacts with 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (HBpin), under ambient reaction conditions in THF, to form the iodoalkylborate species 2-(4-iodobutoxy)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (4-IboxBpin). Apparently, one-half equivalent of I2 reacts with HBpin to form IBpin in pentanes, which in turn cleaves THF to form the 4-IboxBpin. Alkyl and aryl Grignard reagents, prepared under Barbier conditions, then react with 4-IboxBpin to form the corresponding alkyl and aryl pinacolboronates while reforming and liberating THF as the leaving group.
Investigation of a lithium-halogen exchange flow process for the preparation of boronates by using a cryo-flow reactor
Newby, James A.,Huck, Lena,Blaylock, D. Wayne,Witt, Paul M.,Ley, Steven V.,Browne, Duncan L.
, p. 263 - 271 (2014)
Conducting low-temperature organometallic reactions under continuous flow conditions offers the potential to more accurately control exotherms and thus provide more reproducible and scalable processes. Herein, progress towards this goal with regards to the lithium-halogen exchange/borylation reaction is reported. In addition to improving the scope of substrates available on a research scale, methods to improve reaction profiles and expedite purification of the products are also described. On moving to a continuous system, thermocouple measurements have been used to track exotherms and provide a level of safety for continuous processing of organometallic reagents. The use of an in-line continuous liquid-liquid separation device to circumvent labour intensive downstream off-line processing is also reported. A cool setup: A small footprint, modular setup based around a cryo-flow reactor is reported for the preparation of gram quantities of boronic esters. With minimum alteration, including the addition of a data logger with thermocouples and a liquid-liquid separator, the same equipment can be used to scale the process, inclusive of an in-line extraction. Copyright
An opportunity for Mg-catalyzed grignard-type reactions: Direct coupling of benzylic halides with pinacolborane with 10 mol % of magnesium
Pintaric, Christine,Olivero, Sandra,Gimbert, Yves,Chavant, Pierre Y.,Dunach, Elisabet
, p. 11825 - 11827 (2010)
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.
Pd II -Porphyrin Complexes - The First Use as Safer and Efficient Catalysts for Miyaura Borylation
Rao, Kanusu Umamaheswara,Venkateswarlu, Katta
, p. 1055 - 1060 (2018)
We have developed a simple and convenient procedure for the preparation of pinacol arylboronates from aryl/heteroaryl bromides and bis(pinacolato)diborane using a Pd II -porphyrin complex as a catalyst. Seven different Pd II -porphyrin complexes (Pd II -T m HPP, Pd II -T m CPP, Pd II -TPP, Pd II -TST p SPP, Pd II -T p CPP, Pd II -T p TP, and Pd II -T p AP) have been synthesized and investigated for their catalytic influence in the Miyaura borylation.
Remote steric control for undirected meta-selective C-H activation of arenes
Asako, Sobi,Ilies, Laurean,Jin, Yushu,Ramadoss, Boobalan
, p. 658 - 663 (2022/02/21)
Regioselective functionalization of arenes remains a challenging problem in organic synthesis. Steric interactions are often used to block sites adjacent to a given substituent, but they do not distinguish the remaining remote sites. We report a strategy
Photo-induced thiolate catalytic activation of inert Caryl-hetero bonds for radical borylation
K?nig, Burkhard,Wang, Hua,Wang, Shun
supporting information, p. 1653 - 1665 (2021/06/17)
Substantial effort is currently being devoted to obtaining photoredox catalysts with high redox power. Yet, it remains challenging to apply the currently established methods to the activation of bonds with high bond dissociation energy and to substrates with high reduction potentials. Herein, we introduce a novel photocatalytic strategy for the activation of inert substituted arenes for aryl borylation by using thiolate as a catalyst. This catalytic system exhibits strong reducing ability and engages non-activated Caryl–F, Caryl–X, Caryl–O, Caryl–N, and Caryl–S bonds in productive radical borylation reactions, thus expanding the available aryl radical precursor scope. Despite its high reducing power, the method has a broad substrate scope and good functional-group tolerance. Spectroscopic investigations and control experiments suggest the formation of a charge-transfer complex as the key step to activate the substrates.
Arene borylation through C–H activation using Cu3(BTC)2 as heterogeneous catalyst
Dhakshinamoorthy, Amarajothi,García, Cristina Vallés,Concepcion, Patricia,Garcia, Hermenegildo
, p. 212 - 217 (2020/07/06)
C–H borylation by diborane is an important process to access organoboron compounds. Noble metals, including Ir and Rh-based complexes either in the form of homogeneous or heterogeneous catalysts, have been reported to promote arene C–H borylation. Recently, metal organic frameworks (MOFs) having Ir and Co as active sites have been used as catalysts, but they require co-catalysts. In the present study, commercially available Cu3(BTC)2 (BTC: 1,3,5-benzenetricarboxylate) MOF is reported as an effective catalyst to promote borylation of arenes through C–H activation employing bis(pinacolato)diboron (1) as reagent leading to benzylic and aromatic borylation products. Interestingly, other related MOFs like MIL-101(Cr) and Al(OH)(BDC) (BDC: 1,4-benzenedicarboxylate) do not exhibit catalytic activity under identical conditions. Mechanistic studies using in-situ IR spectroscopy reveal that Cu ions play a crucial role in activating the arene and B–B bond in 1.
Preparation method of aryl borate catalyzed by cesium neovalerate
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Paragraph 0034-0037; 0068-0069, (2021/09/22)
The preparation method comprises the following steps: dissolving a compound of formula (I) and a diboron compound in an organic solvent, then adding an organic solvent dissolved with cesium neovalerate, palladium acetate and triphenylphosphine, and carrying out reaction to obtain aryl boronic acid ester. In the formula (I) R1. R2, R3, R4 and R5 are each independently selected from H, C. 1 - C10 Alkyl group, C2 - C10 Alkenyl, C2 - C10 Alkynyl group, C1 - C10 Alkoxy, hydroxy, hydroxy-substituted C1 - C10 Alkyl, phenyl, C1 - C10 Alkylamino. X Is selected from F, Cl, Br, i. The preparation method has the advantages of low production cost, high product yield, high purity, simple operation and suitability for industrial mass production.
Catalytic Boration of Alkyl Halides with Borane without Hydrodehalogenation Enabled by Titanium Catalyst
Wang, Xianjin,Cui, Penglei,Xia, Chungu,Wu, Lipeng
supporting information, p. 12298 - 12303 (2021/05/07)
An unprecedented and general titanium-catalyzed boration of alkyl (pseudo)halides (alkyl-X, X=I, Br, Cl, OMs) with borane (HBpin, HBcat) is reported. The use of titanium catalyst can successfully suppress the undesired hydrodehalogenation products that prevail using other transition-metal catalysts. A series of synthetically useful alkyl boronate esters are readily obtained from various (primary, secondary, and tertiary) alkyl electrophiles, including unactivated alkyl chlorides, with tolerance of other reducing functional groups such as ester, alkene, and carbamate. Preliminary studies on the mechanism revealed a possible radical reaction pathway. Further extension of our strategy to aryl bromides is also demonstrated.
