Modified Ullmann coupling of 2-chloro-3-trifluoromethylpyridine

• Published in: Journal of fluorine chemistry Vol. 73; no. 1; pp. 1 - 6
• Main Authors: Munavalli, S., Rossman, D.I., Szafraniec, L.L., Beaudry, W.T., Rohrbaugh, D.K., Ferguson, C.P., Grätzel, M.
• Format: Journal Article
• Language: English
• Published: LAUSANNE 1 Elsevier B.V 01.07.1995; Elsevier
• Subjects: Bis(trifluoromethyl)bipyridine; Chemistry; Chemistry, Inorganic & Nuclear; Chemistry, Organic; Chlorotrifluoromethylpyridine; Mass spectrometry; NMR spectroscopy; Physical Sciences; Science & Technology; Synthesis; Ullmann coupling; Chlorotrifluoromethylpyridine; Ullmann coupling; Synthesis; NMR spectroscopy; Mass spectrometry; Bis(trifluoromethyl)bipyridine; NICKEL-COMPLEXES; ELECTRON-TRANSFER; HETEROCYCLES; CHLOROTRIFLUOROMETHYLPYRIDINE; ULLMANN COUPLING; SYNTHESIS; MASS SPECTROMETRY; RUTHENIUM; BIS(TRIFLUOROMETHYL)BIPYRIDINE; NMR SPECTROSCOPY; GRIGNARD-REAGENTS; WATER
• ISSN: 0022-1139; 1873-3328
• DOI: 10.1016/0022-1139(94)03168-Y

The application of the modified Ullmann reaction to 2-chloro-3-trifluoromethylpyridine furnishes 5,5′-bis(trifluoromethyl)-2,2′-bipyridine as the primary product, accompanied by small amounts of the expected 3,3′-bis(trifluoromethyl)-2,2′-bipyridine, 2-benzyl-3-(trifluoromethyl)pyridine, bibenzyl, 3-trifluoromethylpyridine, 3-methylpyridine, 2-hydroxyethyl-(3-trifluoromethylpyridyl) ether and 2-hydroxyethyl-(3-methylpyridyl) ether. For comparison purposes, a sample of 3,3′-bis-(trifluoromethyl)-2,2′-bipyridyl was prepared by the treatment of 2,2′-bipyridyl-3,3′-dicarboxylic acid with sulfur tetrafluoride. The formation of all but two compounds mentioned above can be rationalized on the basis of the single-electron-transfer process.