- Para-Selective C-H Borylation of Common Arene Building Blocks Enabled by Ion-Pairing with a Bulky Countercation
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The selective functionalization of C-H bonds at the arene para position is highly challenging using transition metal catalysis. Iridium-catalyzed borylation has emerged as a leading technique for arene functionalization, but there are only a handful of strategies for para-selective borylation, which operate on specific substrate classes and use bespoke ligands or catalysts. We describe a remarkably general protocol which results in para-selectivity on some of the most common arene building blocks (anilines, benzylamines, phenols, benzyl alcohols) and uses standard borylation ligands. Our strategy hinges upon the facile conversion of the substrates into sulfate or sulfamate salts, wherein the anionic arene component is paired with a tetrabutylammonium cation. We hypothesize that the bulk of this cation disfavors meta-C-H borylation, thereby promoting the challenging para-selective reaction.
- Mihai, Madalina T.,Williams, Benjamin D.,Phipps, Robert J.
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supporting information
p. 15477 - 15482
(2019/10/11)
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- A 3 - amino - 4 - chlorophenyl boronic acid [...] alcohol ester synthesis method (by machine translation)
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The invention relates to a 3 - amino - 4 - chlorophenyl boronic acid [...] alcohol ester synthesis method. Mainly solves the technical problem of improving its yield. The invention synthetic method comprises the following steps: in [1, 1' - double-(diphenyl phosphino) ferrocene] palladium dichloride under the catalytic action of, 5 - bromo - 2 - chloro nitrobenzene in 1, 4 - dioxane and duplex [...] borate reaction, to obtain compound 1; compound 1 in ethanol and water in the mixed solution and ammonium chloride, iron powder reaction, nitro is reduced to the amino, to produce the target compound 2. As the expensive medicine intermediate, 3 - amino - 4 - chlorophenyl boronic acid ester in [...] widely applied in the pharmaceutical industry. (by machine translation)
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Paragraph 0005; 0008-0010
(2018/03/01)
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- Synthesis of trimethylstannyl arylboronate compounds by sandmeyer-type transformations and their applications in chemoselective cross-coupling reactions
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A synthetic method based on Sandmeyer-type reactions to access both tin- and boron-substituted arenes from nitroaniline derivatives is described. This transformation can be applied to the synthesis of a series of functionalized trimethylstannyl arylboronates. In addition, the chemoselective reaction of the Stille and Suzuki-Miyaura cross-coupling reactions is explored, and a series of m- and p-terphenyl derivatives have been synthesized by conducting consecutive one-pot Stille and Suzuki-Miyaura cross-coupling reactions.
- Qiu, Di,Wang, Shuai,Tang, Shengbo,Meng, He,Jin, Liang,Mo, Fanyang,Zhang, Yan,Wang, Jianbo
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p. 1979 - 1988
(2014/04/03)
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