- Using Data Science To Guide Aryl Bromide Substrate Scope Analysis in a Ni/Photoredox-Catalyzed Cross-Coupling with Acetals as Alcohol-Derived Radical Sources
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Ni/photoredox catalysis has emerged as a powerful platform for C(sp2)–C(sp3) bond formation. While many of these methods typically employ aryl bromides as the C(sp2) coupling partner, a variety of aliphatic radical sources have been investigated. In principle, these reactions enable access to the same product scaffolds, but it can be hard to discern which method to employ because nonstandardized sets of aryl bromides are used in scope evaluation. Herein, we report a Ni/photoredox-catalyzed (deutero)methylation and alkylation of aryl halides where benzaldehyde di(alkyl) acetals serve as alcohol-derived radical sources. Reaction development, mechanistic studies, and late-stage derivatization of a biologically relevant aryl chloride, fenofibrate, are presented. Then, we describe the integration of data science techniques, including DFT featurization, dimensionality reduction, and hierarchical clustering, to delineate a diverse and succinct collection of aryl bromides that is representative of the chemical space of the substrate class. By superimposing scope examples from published Ni/photoredox methods on this same chemical space, we identify areas of sparse coverage and high versus low average yields, enabling comparisons between prior art and this new method. Additionally, we demonstrate that the systematically selected scope of aryl bromides can be used to quantify population-wide reactivity trends and reveal sources of possible functional group incompatibility with supervised machine learning.
- Doyle, Abigail G.,Gandhi, Shivaani S.,Jiang, Shutian,Kariofillis, Stavros K.,Martinez Alvarado, Jesus I.,?urański, Andrzej M.
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supporting information
p. 1045 - 1055
(2022/01/19)
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- Facile one-pot transformation of arenes into aromatic nitriles under metal-cyanide-free conditions
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Electron-rich arenes bearing methyl or methoxy groups on the aromatic ring were treated with dichloromethyl methyl ether and ZnBr2, and then with molecular iodine and aq. ammonia to give the corresponding aromatic nitriles in good yields. Using this method, febuxostat was efficiently prepared from 4-bromophenol in four steps. The method can be used for the preparation of aromatic nitriles from arenes in one pot under metal-cyanide-free conditions. Various electron-rich arenes could be effectively converted into the corresponding aromatic nitriles in good yields, by treatment with ZnBr2 and dichloromethyl methyl ether, followed by reaction with molecular iodine and aq. ammonia.
- Tamura, Toshiyuki,Moriyama, Katsuhiko,Togo, Hideo
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p. 2023 - 2029
(2015/03/18)
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- CONVENIENT METHOD OF OBTAINING 2-CYANO-4-ALKYLPHENOLS, 4-CYANOPHENOL AND 4-CYANOANILINE.
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A convenient method is described of obtaining 2-cyano-4-alkylphenols and 4-cyanophenol by substituting brombine atom for the cyano group in the respective bromoanisoles and demethylation of the cyanoalkylanisoles. It is suggested to prepare 4-cyanoaniline by reduction of 4-cyano-nitrobenzene with aqueous hydrazine solutions.
- Adamska,Dabrowski,Dziabuszek
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