- Nickel-Catalyzed Reductive Cross-Coupling of Benzyl Halides with Aryl Halides
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Systematic studies of the coupling of benzylic with aryl halides are presented. The optimized reaction conditions for electron-deficient aryl halides cannot be applied to the electron-rich or neutral counterparts, and vice versa. The excellent functional group tolerance and broad substrate scope may enable the current work to be useful for the construction of diaryl methane products.
- Zhang, Qingchen,Wang, Xuan,Qian, Qun,Gong, Hegui
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supporting information
p. 2829 - 2836
(2016/08/31)
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- The direct anti-Markovnikov addition of mineral acids to styrenes
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The direct anti-Markovnikov addition of strong Bronsted acids to alkenes remains an unsolved problem in synthetic chemistry. Here, we report an efficient organic photoredox catalyst system for the addition of HCl, HF and also phosphoric and sulfonic acids to alkenes, with complete regioselectivity. These transformations were developed using a photoredox catalyst in conjunction with a redox-active hydrogen atom donor. The nucleophile counterion plays a critical role by ensuring high reactivity, with 2,6-lutidinium salts typically furnishing the best results. The nature of the redox-active hydrogen atom donor is also consequential, with 4-methoxythiophenol providing the best reactivity when 2,6-lutidinium salts are used. A novel acridinium sensitizer provides enhanced reactivity within several of the more challenging reaction manifolds. This Article demonstrates how nucleophilic addition reactions mediated by photoredox catalysis can change the way electrophilic and homofugal precursors are constructed.
- Wilger, Dale J.,Grandjean, Jean-Marc M.,Lammert, Taylor R.,Nicewicz, David A.
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p. 720 - 726
(2014/08/05)
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- Copper-catalyzed nucleophilic trifluoromethylation of benzylic chlorides
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Reactions of primary and secondary benzylic chlorides with trifluoromethyltrimethylsilane in the presence of a catalytic amount of copper(i) thiophene-2-carboxylate (CuTC) have been found to give the corresponding benzylic trifluoromethylated products in good to high yields. the Partner Organisations 2014.
- Miyake, Yoshihiro,Ota, Shin-Ichi,Shibata, Masashi,Nakajima, Kazunari,Nishibayashi, Yoshiaki
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supporting information
p. 5594 - 5596
(2014/07/22)
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- Solvolysis of 1-alkyl-1-chloro-1-(4-methyl)phenylmethanes. Nucleophilic solvent intervention and extended YBnCl scale
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The solvolysis of 1-alkyl-1-chloro-1-(4-methyl)phenylmethanes (4a-d) in aqueous acetone, aqueous ethanol, aqueous methanol and ethanol-trifluoroethanol was studied. Grunwald-Winstein-type correlation analysis using the YBnCl scale suggests significant nucleophilic solvent intervention in the case of 1-chloro-1-(4-methyl)phenylethane (4a). Increasing bulkiness of the 1-alkyl substituent from methyl (4a) to ethyl (4b), to isopropyl (4c) and to tert-butyl (4d) resulted in a gradual change to limiting SN1 mechanisms. The observed excellent linear correlations with YBnCl and the good solubility in high-water-containing binary solvents made 4d a suitable reference standard for deriving more YBnCl values. A positive azide salt effect was realized in the solvolysis of 4a but not 4d. A small decrease in the β-deuterium kinetic isotope effect from 4a to 1-chloro-1-(4-methoxyphenyl)propane (5) suggested the presence of additional stabilization of the benzylic cationic transition state. However, no relationship between k(CH3)/k(CD3) and the solvent effect was found. The superiority of employing the YBnCl scale over the combination of YCl and I scales in the mehanistic study was observed.
- Liu, Kwang-Ting,Chang, Lih-Wie,Yu, Der-Gann,Chen, Pang-Shao,Fan, Ju-Ta
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p. 879 - 884
(2007/10/03)
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