Novel Synthesis of 7-Fluoro-8-(trifluoromethyl)- 1<i>H</i>-1,6-naphthyridin-4-one Derivatives: Intermolecular Cyclization of an <i>N</i>-Silyl-1-azaallyl Anion with Perfluoroalkene and Subsequent Intramolecular Skeletal Transformation of the Resulting Pentasubstituted Pyridines

In this study, fluorine-containing pentasubstituted pyridine derivatives 9a−m were prepared regioselectively in good yields by the intermolecular cyclization of a variety of N-silyl-1-azaallylic anion intermediates 7, which were generated from a functionalized silane 5 and an aromatic/aliphatic nitrile 6 with perfluoroalkene 8. Also, 7-fluoro-8-(trifluoromethyl)-1H-1,6-naphthyridin-4-one derivatives 11a−k were synthesized in excellent yields by the subsequent base-promoted intramolecular skeletal transformation of the resulting pyridine derivatives 10a−k.