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Mečiarová, Mária; Toma, Štefan; Loupy, André; Horváth, Branislav
Phosphorus, sulfur, and silicon and the related elements, 01/2008, Letnik: 183, Številka: 1Journal Article
Solvent-free reactions of 2- and 3-halopyridines with PPh 3 , PBu 3 , and PCy 3 were studied under conventional heating, as well as under microwave irradiation. No difference was observed in the reaction course between classical and microwave reactions. 2-Bromopyridine gave quantitative yields of 2-pyridyltriphenylphosphonium bromide within few minutes at 190°C. Equimolar amounts of some inorganic salts (LiPF 6 , LiOTf, LiBr, NaPF 6 , KPF 6 ) were necessary for the reactions of the other 2-halopyridines. 3-Halopyridines did not react with PPh 3 even in the presence of LiPF 6 . Their reactions with PCy 3 in the presence of LiPF 6 resulted in the quantitative formation of dicyclohexylphosphine oxide.
