- Site-Selective Pd-Catalyzed C(sp3)?H Arylation of Heteroaromatic Ketones
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A ligand-controlled site-selective C(sp3)?H arylation of heteroaromatic ketones has been developed using Pd catalysis. The reaction occurred selectively at the α- or β-position of the ketone side-chain. The switch from α- to β-arylation was realized by addition of a pyridone ligand. The α-arylation process showed broad scope and high site- and chemoselectivity, whereas the β-arylation was more limited. Mechanistic investigations suggested that α-arylation occurs through C?H activation/oxidative addition/reductive elimination whereas β-arylation involves desaturation and aryl insertion.
- Kudashev, Anton,Baudoin, Olivier
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supporting information
p. 17688 - 17694
(2021/11/16)
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- Iron-catalyzed Minisci acylation of N-heteroarenes with α-keto acids
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An efficient and mild protocol has been developed for the Minisci acylation reactions of nitrogen-containing heteroarenes with α-keto acids. Distinct from the conventional Minisci acylation conditions, the chemistry was performed using non-noble metal Fe(II), instead of expensive Ag(I) salt, as catalyst. A wide range of substrates, including aliphatic or aromatic α-keto acids, as well as various N-heteroarenes, proved to be compatible with the protocol. Scale-up experiment also demonstrates the practicality of the approach.
- Wang, Xiu-Zhi,Zeng, Cheng-Chu
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supporting information
p. 1425 - 1430
(2019/02/01)
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- Homolytic Acylation of Protonated Pyridines and Pyrazines with α-Keto Acids: The Problem of Monoacylation
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The silver-catalyzed decarboxylation of α-keto acids by persulfate leads to acyl radicals, which can effect the selective homolytic acylation of pyridine and pyrazine derivatives.Compared with the previously developed source of acyl radicals by hydrogen abstraction from aldehydes, this procedure is more effective in monoacylation when multiple positions of high nucleophilic reactivity are available in the heterocyclic ring.Although the introduction of an acyl group strongly activates the heterocyclic ring toward further substitution, monoacylation can be achieved by taking advantage of the difference in basicity and lipophilicity between the starting base and the monoacylation products in a two-phase system.
- Fontana, Francesca,Minisci, Francesco,Barbosa, Maria Claudia Nogueira,Vismara, Elena
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p. 2866 - 2869
(2007/10/02)
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- Preparation of Monoacylpyrazines
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Homolytic acylation of pyrazine and alkylpyrazines by aldehydes, as a source of an acyl radical, gives mainly monoacylation products.The reactions proceed in reasonable yields and provide a new route to pyrazine ketones.
- Houminer, Y.,Southwick, E. W.,Williams, D. L.
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p. 497 - 500
(2007/10/02)
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