- NNB-type tridentate boryl ligands enabling a highly active iridium catalyst for C–H borylation
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Boryl ligands play a very important role in catalysis because of their very high electron-donating property. In this paper, NNB-type boryl anions were designed as tridentate ligands to promote aryl C–H borylation. In combination with [IrCl(COD)]2/su
- Ding, Siyi,Wang, Linghua,Miao, Zongcheng,Li, Pengfei
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- meta-Nitration of Arenes Bearing ortho/para Directing Group(s) Using C?H Borylation
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Herein, we report the meta-nitration of arenes bearing ortho/para directing group(s) using the iridium-catalyzed C?H borylation reaction followed by a newly developed copper(II)-catalyzed transformation of the crude aryl pinacol boronate esters into the corresponding nitroarenes in a one-pot fashion. This protocol allows the synthesis of meta-nitrated arenes that are tedious to prepare or require multistep synthesis using the existing methods. The reaction tolerates a wide array of ortho/para-directing groups, such as ?F, ?Cl, ?Br, ?CH3, ?Et, ?iPr ?OCH3, and ?OCF3. It also provides regioselective access to the nitro derivatives of π-electron-deficient heterocycles, such as pyridine and quinoline derivatives. The application of this method is demonstrated in the late-stage modification of complex molecules and also in the gram-scale preparation of an intermediate en route to the FDA-approved drug Nilotinib. Finally, we have shown that the nitro product obtained by this strategy can also be directly converted to the aniline or hindered amine through Baran's amination protocol.
- Li, Xuejing,Deng, Xingwang,Coyne, Anthony G.,Srinivasan, Rajavel
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supporting information
p. 8018 - 8023
(2019/05/29)
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- Sterically controlled C-H/C-H homocoupling of arenes: Via C-H borylation
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A mild one-pot protocol for the synthesis of symmetrical biaryls by sequential Ir-catalyzed C-H borylation and Cu-catalyzed homocoupling of arenes is described. The regiochemistry of the biaryl formed is sterically controlled as dictated by the C-H borylation step. The methodology is also successfully extended to heteroarenes. Some of the products obtained by this approach are impossible to obtain via the Ullmann or the Suzuki coupling protocols. Finally, we have shown a one-pot sequence describing C-H borylation/Cu-catalyzed homocoupling/Pd-catalyzed Suzuki coupling to obtain π-extended arene frameworks.
- Pei, Xiaocong,Zhou, Guan,Li, Xuejing,Xu, Yuchen,Panicker, Resmi C.,Srinivasan, Rajavel
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supporting information
p. 5703 - 5707
(2019/06/19)
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- Double N,B-Type Bidentate Boryl Ligands Enabling a Highly Active Iridium Catalyst for C-H Borylation
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Boryl ligands hold promise in catalysis due to their very high electron-donating property. In this communication double N,B-type boryl anions were designed as bidentate ligands to promote an sp2 C-H borylation reaction. A symmetric pyridine-con
- Wang, Guanghui,Xu, Liang,Li, Pengfei
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supporting information
p. 8058 - 8061
(2015/07/15)
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- A general strategy for the perfluoroalkylation of arenes and arylbromides by using arylboronate esters and [(phen)CuRF]
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A versatile method for the synthesis of aryl perfluoroalkanes from arenes and aryl bromides is described. Substituted arenes or aryl bromides are converted in situ to an aryl boronate ester that readily undergoes perfluoroalkylation in air with [(phen)CuRF]. A broad range of aryl bromide substrates were perfluoroalkylated in good yield for the first time. [(phen)CuCF3] is now commercially available and has been prepared on 20g scale. Copyright
- Litvinas, Nichole D.,Fier, Patrick S.,Hartwig, John F.
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supporting information; experimental part
p. 536 - 539
(2012/02/16)
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- Efficient and complementary methods offering access to synthetically valuable 1,2-dibromobenzenes
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1,2-Dibromobenzenes are highly valuable precursors for various organic transformations, in particular, reactions based on the intermediate formation of benzynes. This report describes short sequences for the synthesis of various derivatives based on regioselective bromination, ortho-metalation, and halogen/metal permutations. 1,2-Dibromo-3-iodobenzene (2f), 1,2-dibromo-4- iodobenzene (4c), and 2,3-dibromo-1,4-diiodobenzene (5e) act as intermediates in these syntheses. Bromo-iodoarenes have been synthesized by short and regioselective bromination or iodination sequences that combine ortho-metalation, halo-desilylation, diazotation, or bromination reactions of anilines. These polyhalo derivatives were then used as key intermediates to access a wide range of functionalized 1,2-dibromobenzenes by chemoselective organometallic reactions. Copyright
- Diemer, Vincent,Leroux, Frederic R.,Colobert, Fracoise
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p. 327 - 340
(2011/02/26)
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- Iridium-catalyzed preparation of silylboranes by silane borylation and their use in the catalytic borylation of arenes
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Silylboranes are versatile reagents for transition metal-catalyzed reactions of unsaturated organic molecules. These reagents are typically prepared by the addition of a silyl lithium species to a boron electrophile. However, the need to generate anionic silane reagents limits the scope of silylboranes that can be readily obtained. Here, we describe the synthesis of trialkylsilylboranes by the borylation of silanes catalyzed by iridium complexes. The reaction of trialkylhydrosilanes with B2pin 2 catalyzed by the combination of [Ir(OMe)cod]2 and 4,4′-di-tert-butylbipyridine forms trialkylsilylboronic esters. In addition, we show that these trialkylsilylboranes serve as boron sources for the iridium-catalyzed borylation of aryl C-H bonds. In contrast to diboron reagents, the silylboranes react with methylarenes at both the aryl and methyl C-H bonds.
- Boebel, Timothy A.,Hartwig, John F.
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p. 6013 - 6019
(2009/04/13)
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