- Refining boron-iodane exchange to access versatile arylation reagents
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Aryl(Mes)iodonium salts, which are multifaceted aryl transfer reagents, are synthesized via boron-iodane exchange. Modification to both the nucleophilic (aryl boron) and electrophilic (mesityl-λ3-iodane) reaction components results in improved yield and faster reaction time compared to previous conditions. Mechanistic studies reveal a pathway that is more like transmetallation than SEAr.
- Karandikar, Shubhendu S.,Stuart, David R.
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supporting information
p. 1211 - 1214
(2022/02/03)
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- Transition-Metal-Free Borylation of Aryl Bromide Using a Simple Diboron Source
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In this study, we developed a simple transition-metal-free borylation reaction of aryl bromides. Bis-boronic acid (BBA), was used, and the borylation reaction was performed using a simple procedure at a mild temperature. Under mild conditions, aryl bromides were converted to arylboronic acids directly without any deprotection steps and purified by conversion to trifluoroborate salts. The functional group tolerance was considerably high. The mechanism study suggested that this borylation reaction proceeds via a radical pathway.
- Han, Min Su,Lim, Taeho,Ryoo, Jeong Yup
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p. 10966 - 10972
(2020/09/23)
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- The facile and direct formylation of organoboron aromatic compounds with benzodithiolylium tetrafluoroborate
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Organoboron compounds can be used to effect a direct formylation in the absence of transition metals. We report that the direct reaction between boronic derivatives and benzodithiolylium tetrafluoroborate, a commercially available carbenium ionic compound, is possible and provides access to many interesting compounds without the use of transition metals. The direct reaction of the carbenium ion with boronic derivatives results in the formation of substituted arylcarbenium ions, a number of which can be further utilized in materials chemistry or for the direct transformation into other compounds. In addition to the rich chameleonic chemical nature of the benzodithiol intermediate, such species can also undergo a metallation reaction and subsequent treatment with a wide range of electrophiles to access a variety of functional groups (aldehyde, ketone, acid, and alkyl groups). Copyright
- Petruzziello, Diego,Gualandi, Andrea,Jaffar, Hamza,Lopez-Carrillo, Veronica,Cozzi, Pier Giorgio
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p. 4909 - 4917
(2013/08/23)
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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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- Scope of the palladium-catalyzed aryl borylation utilizing bis-boronic acid
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The Suzuki-Miyaura reaction has become one of the more useful tools for synthetic organic chemists. Until recently, there did not exist a direct way to make the most important component in the coupling reaction, namely the boronic acid. Current methods to make boronic acids often employ harsh or wasteful reagents to prepare boronic acid derivatives and require additional steps to afford the desired boronic acid. The scope of the previously reported palladium-catalyzed, direct boronic acid synthesis is unveiled, which includes a wide array of synthetically useful aryl electrophiles. It makes use of the newly available second generation Buchwald XPhos preformed palladium catalyst and bis-boronic acid. For ease of isolation and to preserve the often sensitive C-B bond, all boronic acids were readily converted to their more stable trifluoroborate counterparts.
- Molander, Gary A.,Trice, Sarah L. J.,Kennedy, Steven M.,Dreher, Spencer D.,Tudge, Matthew T.
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supporting information; experimental part
p. 11667 - 11673
(2012/09/05)
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- PROCESSES FOR THE PREPARATION OF BIPHENYL COMPOUNDS
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The invention concerns processes for the synthesis of a compound of the formula: wherein: R1 and R2 are each, independently, C1-C12 alkyl, CO2R3, OR4, R5(OR6), or C6-C18 aiyl; R3 -R6 are each, independently, C1-C12 alkyl or C6-C12 aryl; and n and m are each, independently, O or an integer from 1-5; said process comprising: — contacting a compound of the formula H0-R7-0H with BH3 and a compound of the formula in the presence of a nickel-containing catalyst to produce a first product, where R7 is a C2-C12 hydrocarbon group and X is a halogen, OMs or OTs; — contacting the first product in situ with a compound of the formula: in the presence of a nickel-containing catalyst to produce a compound of formula I, where Z is a halogen.
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Page/Page column 19
(2010/01/29)
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- Sequential Ni-catalyzed borylation and cross-coupling of aryl halides via in situ prepared neopentylglycolborane
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(Chemical Equation Presented) A procedure for NiCl2(dppp)- catalyzed pinacolborylation and neopentylglycolborylation that utilizes in situ prepared inexpensive pinacolborane and neopentylglycolborane is reported. The scope of this reaction was demonstrated with a variety of aryl bromides and iodides. The resulting aryl neopentylglycolboronic esters undergo a NiCl 2(dppe)-catalyzed cross-coupling with aryl halides, resulting in an extremely efficient and cost-effective method for the synthesis of functional biaryls, dendritic building blocks, and other complex architectures.
- Rosen, Brad M.,Huang, Chenghong,Percec, Virgil
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supporting information; experimental part
p. 2597 - 2600
(2009/05/27)
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