Mechanochemical Defluorinative Arylation of Trifluoroacetamides: An Entry to Aromatic Amides
Satenik Mkrtchyan*, Mohanad Shkoor, Mandalaparthi Phanindrudu, Miroslav Medved', Olena Sevastyanova and Viktor O. Iaroshenko*
*Department of Chemistry, Faculty of Natural Sciences, Matej Bel University, Tajovského 40, 97401 Banská Bystrica, Slovakia,
Email: mkrtchyan.satenik
umb.sk, viktor.iaroshenkoumb.sk
S. Mkrtchyan, M. Shkoor, M. Phanindrudu, M. Medved', O. Sevastyanova, V. O. Iaroshenko, J. Org. Chem., 2023, 88, 863-870.
DOI: 10.1021/acs.joc.2c02197
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Abstract
A mechanochemically induced nickel-catalyzed defluorinative arylation of aliphatic and aromatic trifluoroacetamides with either arylboronic acids, trimethoxyphenylsilanes, diaryliodonium salts, or dimethyl(phenyl)sulfonium salts with trifluoroacetamides affords substituted aromatic amides in good yields. These reactions are enabled by C-CF3 bond activation using Dy2O3 as an additive.
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Energy diagram (ΔG°in kcal/mol;T= 298.15K)
General procedure for the synthesis of amides starting from trifluoroacetamides and boronic acids
In dry box, to 5 mL grinding vessel (made of stainless) equipped with two balls (made of stainless, diameter: 5 mm) was placed consequently NiBr2 (22 mg, 0.1 mmol, 10 mol%), cucurbit[6]uril (100 mg, 0.1 mmol, 10 mol%), Dy2O3 (373 mg, 1.0 mmol, 1.0 equiv.), DABCO (157 mg, 1.4 mmol, 1.4 equiv.); then appropriate boronic acid (1.2 mmol, 1.2 equiv.) and appropriate trifluoroacetamide 1 (1.0 mmol, 1.0 equiv.) were added and the reaction vessel was properly capped. Finally, the vessel was installed on the mill and subjected to milling at 30Hz for 90 minutes. After completion of the reaction, the content of the vessel was generously treated with distilled water, filtrated and finally properly dried in vacuum. The resulted crude was directly subjected to gradient flash chromatography on silica gel to isolate the desired amide derivative. The gram scale synthesis was performed on 10 mmol of the starting amide in 25 mL grinding vessel using three 10 mm balls.
Key Words
carboxylations, mechanochemistry
ID: J42-Y2023
