- Electrochemical ipso-Thiocyanation of Arylboron Compounds
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An operationally simple electrochemical method for the transition-metal-free ipso-thiocyanation of arylboronic acids and aryl trifluoroborates has been developed. The SCN electrophile is generated in situ by anodic oxidation of thiocyanate anions, which avoids formation of salt waste and prevents unwanted side reactions arising from chemical oxidants. The reaction proceeds regiospecifically, and the scope extends to non-activated aromatic systems. (Figure presented.).
- Dyga, Marco,Hayrapetyan, Davit,Rit, Raja K.,Goo?en, Lukas J.
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supporting information
p. 3548 - 3553
(2019/04/26)
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- A Revised Modular Approach to (–)-trans-Δ8-THC and Derivatives Through Late-Stage Suzuki–Miyaura Cross-Coupling Reactions
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A revised modular approach to various synthetic (–)-trans-Δ8-THC derivatives through late-stage Suzuki–Miyaura cross-coupling reactions is disclosed. Ten derivatives were synthesized allowing both sp2- and sp3-hybridized cross-coupling partners with minimal β-hydride elimination. Importantly, we demonstrate that a para-bromo-substituted THC scaffold for Suzuki–Miyaura cross-coupling reactions has been initially reported incorrectly in recent literature.
- Bloemendal, Victor R. L. J.,Sondag, Daan,Elferink, Hidde,Boltje, Thomas J.,van Hest, Jan. C. M.,Rutjes, Floris P. J. T.
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p. 2289 - 2296
(2019/04/03)
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- Alkali metal salts with designable aryltrifluoroborate anions
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Aryltrifluoroborate ([ArBF3]-) has a designable basic anion structure. Various [ArBF3]--based anions were synthesized to create novel alkali metal salts using a simple and safe process. Nearly 40 novel alkali metal salts were successfully obtained, and their physicochemical characteristics, particularly their thermal properties, were elucidated. These salts have lower melting points than those of simple inorganic alkali halide salts, such as KCl and LiCl, because of the weaker interactions between the alkali metal cations and the [ArBF3]- anions and the anions' larger entropy. Moreover, interestingly, potassium cations were electrochemically reduced in the potassium (meta-ethoxyphenyl)trifluoroborate (K[m-OEtC6H4BF3]) molten salt at 433 K. These findings contribute substantially to furthering molten salt chemistry, ionic liquid chemistry, and electrochemistry.
- Iwasaki, Kazuki,Yoshii, Kazuki,Tsuzuki, Seiji,Matsumoto, Hajime,Tsuda, Tetsuya,Kuwabata, Susumu
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p. 9468 - 9476
(2016/10/30)
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- A modified procedure for the palladium catalyzed borylation/Suzuki-Miyaura cross-coupling of aryl and heteroaryl halides utilizing bis-boronic acid
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Abstract A modified Pd-catalyzed method of forming aryl- and heteroarylboron species and a two-step, one-pot borylation/Suzuki-Miyaura cross coupling using the atom economical tetrahydroxydiboron (bis-boronic acid, BBA) is reported. By using ethylene glycol as an additive, the new method results in increased yields, lower BBA loading, faster reaction times, and a broader reaction scope, including previously problematic substrates such as heterocycles.
- Molander, Gary A.,Trice, Sarah L.J.,Tschaen, Brittany
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p. 5758 - 5764
(2015/08/03)
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- Nickel-catalyzed borylation of halides and pseudohalides with tetrahydroxydiboron [B2(OH)4]
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Arylboronic acids are gaining increased importance as reagents and target structures in a variety of useful applications. Recently, the palladium-catalyzed synthesis of arylboronic acids employing the atom-economical tetrahydroxydiboron (BBA) reagent has been reported. The high cost associated with palladium, combined with several limitations of both palladium- and copper-catalyzed processes, prompted us to develop an alternative method. Thus, the nickel-catalyzed borylation of aryl and heteroaryl halides and pseudohalides using tetrahydroxydiboron (BBA) has been formulated. The reaction proved to be widely functional group tolerant and applicable to a number of heterocyclic systems. To the best of our knowledge, the examples presented here represent the only effective Ni-catalyzed Miyaura borylations conducted at room temperature.
- Molander, Gary A.,Cavalcanti, Livia N.,Garcia-Garcia, Carolina
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p. 6427 - 6439
(2013/07/26)
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- Preparation of organotrifluoroborate salts: Precipitation-driven equilibrium under non-etching conditions
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Simple, rapid, and scaleable: In contrast to current procedures using corrosive HF/MF or MHF2 reagents (M=e.g. K), a wide range of trifluoroborates can be rapidly, simply, and safely prepared from MF (M=K, Cs), RCO2H, and a boronic a
- Lennox, Alastair J. J.,Lloyd-Jones, Guy C.
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supporting information
p. 9385 - 9388
(2012/10/29)
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- Copper-catalyzed amination of potassium aryl trifluoroborates using aqueous ammonia
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The conversion of potassium aryl trifluoroborates containing different functionalities into the corresponding aryl amines using a catalytic amount of CuSO4·5H2O is described. The methodology uses water as a solvent under aerobic conditions to give the products in good yields.
- Liesen, André P.,Silva, Arisson T.,Sousa, Jokderléa C.,Menezes, Paulo H.,Oliveira, Roberta A.
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supporting information; experimental part
p. 4240 - 4242
(2012/08/28)
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- Pd-Catalyzed C-3 functionalization of indolizines via C-H bond cleavage
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New transition metal-catalyzed methods for the arylation of indolizines by the direct cleavage of C-H bonds have been developed. A wide range of aryltrifluoroborate salts react with indolizines in the presence of Pd(OAc) 2 catalyst and AgOAc oxidant to give the arylated indolizines in high yields. Both electron-donating and electron-withdrawing groups perform smoothly while bromide and chlorine substituents are tolerated. In addition, the indolizines display similar reactivities in the Pd-catalyzed reaction with 3-phenylpropiolic acid to afford the corresponding C-3 alkynylated indolizines. These methods allow the direct functionalization of indolizines in one step.
- Zhao, Baoli
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supporting information; experimental part
p. 7108 - 7119
(2012/09/25)
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- Environmentally friendly homocoupling reaction of functionalized potassium aryl trifluoroborates salts in aqueous media
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The homocoupling reaction between potassium aryl trifluoroborates containing different functionalities promoted by a catalytic amount of Pd(OAc)2 is described. The methodology uses water as a solvent under aerobic conditions to give the corresponding biaryl compounds in good yields.
- Santos-Filho, Everaldo F.,Sousa, Jokderléa C.,Bezerra, Natércia M.M.,Menezes, Paulo H.,Oliveira, Roberta A.
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supporting information; experimental part
p. 5288 - 5291
(2011/10/30)
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- Oxidative nucleophilic substitution: Transformation of alkylboronic derivatives
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An efficient amidation reaction is described in this paper. Potassium alkyltrifluoroborate salts can be transforming to amides from nitriles in the presence of copper acetate and boron trifluoride. An extension of this reaction allowed the formation of amines, ethers, and C-C bond.
- Cazorla, Clément,Métay, Estelle,Lemaire, Marc
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experimental part
p. 8615 - 8621
(2011/11/30)
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- Introduction of allyi and prenyl side-chains into aromatic systems by suzuki cross-coupling reactions
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This paper reports some studies aiming at the developement of a general protocol useful for the synthesis of allyl- and prenylaromatic compounds. The first part deals with, the preparation of boron reagents like arylboronic acids and their pinacol esters as well as of pinacol allyl- and prenylboronates. The second part of the paper is devoted to the use of these boron reagents in Suzuki-Miyaura cross-coupling reactions leading to allylation and prenylation of aromatic compounds. Of the six methods studied, the most promising re-suits were obtained by using the Pd2(dba)3-catalyzed reactions of arylboronic acids with allyl and prenyl bromides, that lead to the products of cross coupling in high yields (average 87%), and the reactions of aryl trifluoroborates with allyl and prenyl bromides catalyzed by Pd(OAc)2 that lead to the products of coupling in all cases in high yields (average 82%).
- Gerbino, Dario C.,Mandolesi, Sandra D.,Schmalz, Hans-Guenther,Podesta, Julio C.
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scheme or table
p. 3964 - 3972
(2010/02/27)
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- Potassium organotrifluoroborates: New partners in palladium-catalysed cross-coupling reactions
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The preparation of various potassium organotrifluoroborates bearing either aryl, alkenyl, or alkynyl substituents is described. These stable salts are shown to be very efficient partners in palladium-catalysed cross- coupling reactions with arenediazonium salts, affording biaryl and styrene derivatives in high yields.
- Darses, Sylvain,Michaud, Guillaume,Genet, Jean-Pierre
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p. 1875 - 1883
(2007/10/03)
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