1104636-67-0Relevant academic research and scientific papers
Activation of Aryl Carboxylic Acids by Diboron Reagents towards Nickel-Catalyzed Direct Decarbonylative Borylation
Deng, Xi,Guo, Jiandong,Su, Weiping,Wang, Xiaotai,Zhang, Xiaofeng
, p. 24510 - 24518 (2021/08/12)
The Ni-catalyzed decarbonylative borylation of (hetero)aryl carboxylic acids with B2cat2 has been achieved without recourse to any additives. This Ni-catalyzed method exhibits a broad substrate scope covering poorly reactive non-ortho-substituted (hetero)aryl carboxylic acids, and tolerates diverse functional groups including some of the groups active to Ni0 catalysts. The key to achieve this decarbonylative borylation reaction is the choice of B2cat2 as a coupling partner that not only acts as a borylating reagent, but also chemoselectively activates aryl carboxylic acids towards oxidative addition of their C(acyl)?O bond to Ni0 catalyst via the formation of acyloxyboron compounds. A combination of experimental and computational studies reveals a detailed plausible mechanism for this reaction system, which involves a hitherto unknown concerted decarbonylation and reductive elimination step that generates the aryl boronic ester product. This mode of boron-promoted carboxylic acid activation is also applicable to other types of reactions.
Radical C?N Borylation of Aromatic Amines Enabled by a Pyrylium Reagent
Chabbra, Sonia,Cornella, Josep,Leutzsch, Markus,Ma, Yuanhong,Niski, Jan,Pang, Yue,Reijerse, Edward J.,Schnegg, Alexander
supporting information, (2020/03/23)
Herein, we report a radical borylation of aromatic amines through a homolytic C(sp2)?N bond cleavage. This method capitalizes on a simple and mild activation via a pyrylium reagent (ScPyry-OTf) thus priming the amino group for reacti
Phenoxy-Dialkoxy Borates as a New Class of Readily Prepared Preactivated Reagents for Base-Free Cross-Coupling
Paladino, Marco,Boghi, Michele,Hall, Dennis G.
supporting information, p. 6566 - 6570 (2019/10/22)
One of the most useful chemical transformations of organoboronic acids is the Suzuki–Miyaura cross-coupling reaction. Although it has vast application, it possesses some limitations: boronic acids can be difficult to quantify accurately due to their tendency to form oligomeric anhydrides and they must be activated under basic conditions. To address these problems, a new class of boronic acid derivatives is described. Phenoxy-dialkoxy borates are prepared under mild conditions and show good solubility in common organic solvents. These adducts can be used in base-free metal-catalysed cross-coupling reactions, including orthogonal reactions with MIDA boronates and trifluoroborates.
A simple and mild Suzuki reaction protocol using triethylamine as base and solvent
Li, Xinmin,Zhang, Hang,Hu, Qinghong,Jiang, Bo,Zeli, Yuan
supporting information, p. 3123 - 3132 (2018/12/04)
A simple and mild protocol for the palladium-catalyzed Suzuki reaction of aryl bromides and arylboronic acids is developed. The cross-coupling reactions can be performed at room temperature using 5.0 equiv. of Et3N as solvent and base without any ligands, and affording biaryl products in good yields. In addition, the chemoselecitive Suzuki reaction of bromo-N-methyliminodiacetic acid (MIDA) boronates with arylboronic acids can be achieved in this system, and various unsymmetrical terphenyls have been prepared in moderate yields by one-pot double Suzuki reactions.
Light-Induced Gold-Catalyzed Hiyama Arylation: A Coupling Access to Biarylboronates
Xie, Jin,Sekine, Kohei,Witzel, Sina,Kr?mer, Petra,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
supporting information, p. 16648 - 16653 (2018/12/04)
Organoboron compounds are versatile synthetic building blocks. We herein report a new strategy, a photochemical gold-catalyzed chemo-selective Hiyama arylation of B,Si bifunctionalized reagents with diazonium salts, which is orthogonal to common strategies and therefore a unique tool for synthesis of valuable biarylboronates. With this new methodology a wide array of diversely functionalized sp2- and sp3-hybridized biarylboronates were obtained. Notably, the synergism of gold catalysis with copper catalysis or palladium catalysis, allows for one-pot iterative C?X (heteroatom) and C?C couplings for the rapid assembly of several simple fragments to relatively complex molecules. Mechanistic studies indicated that photosensitizer-free conditions were superior to gold/Ru(bpy)3Cl2 dual catalysis.
Speciation control during Suzuki-Miyaura cross-coupling of haloaryl and haloalkenyl MIDA boronic esters
Fyfe, James W. B.,Valverde, Elena,Seath, Ciaran P.,Kennedy, Alan R.,Redmond, Joanna M.,Anderson, Niall A.,Watson, Allan J. B.
supporting information, p. 8951 - 8964 (2015/06/08)
Boronic acid solution speciation can be controlled during the Suzuki-Miyaura cross-coupling of haloaryl N-methyliminodiacetic acid (MIDA) boronic esters to enable the formal homologation of boronic acid derivatives. The reaction is contingent upon control of the basic biphase and is thermodynamically driven: temperature control provides highly chemoselective access to either BMIDA adducts at room temperature or boronic acid pinacol ester (BPin) products at elevated temperature. Control experiments and solubility analyses have provided some insight into the mechanistic operation of the formal homologation process.
Mechanistic studies into amine-mediated electrophilic arene borylation and its application in MIDA boronate synthesis
Bagutski, Viktor,Del Grosso, Alessandro,Carrillo, Josue Ayuso,Cade, Ian A.,Helm, Matthew D.,Lawson, James R.,Singleton, Paul J.,Solomon, Sophia A.,Marcelli, Tommaso,Ingleson, Michael J.
, p. 474 - 487 (2013/02/25)
Direct electrophilic borylation using Y2BCl (Y2 = Cl2 or o-catecholato) with equimolar AlCl3 and a tertiary amine has been applied to a wide range of arenes and heteroarenes. In situ functionalization of the ArBCl2 products is possible with TMS 2MIDA, to afford bench-stable and easily isolable MIDA-boronates in moderate to good yields. According to a combined experimental and computational study, the borylation of activated arenes at 20 C proceeds through an S EAr mechanism with borenium cations, [Y2B(amine)] +, the key electrophiles. For catecholato-borocations, two amine dependent reaction pathways were identified: (i) With [CatB(NEt 3)]+, an additional base is necessary to accomplish rapid borylation by deprotonation of the borylated arenium cation (σ complex), which otherwise would rather decompose to the starting materials than liberate the free amine to effect deprotonation. Apart from amines, the additional base may also be the arene itself when it is sufficiently basic (e.g., N-Me-indole). (ii) When the amine component of the borocation is less nucleophilic (e.g., 2,6-lutidine), no additional base is required due to more facile amine dissociation from the boron center in the borylated arenium cation intermediate. Borenium cations do not borylate poorly activated arenes (e.g., toluene) even at high temperatures; instead, the key electrophile in this case involves the product from interaction of AlCl3 with Y2BCl. When an extremely bulky amine is used, borylation again does not proceed via a borenium cation; instead, a number of mechanisms are feasible including via a boron electrophile generated by coordination of AlCl3 to Y2BCl, or by initial (heteroarene)AlCl3 adduct formation followed by deprotonation and transmetalation.
