Synthesis of 1-(1-Arylvinyl)pyridin-2(1H)-ones from Ketones and 2-Fluoropyridine

Pyridone skeletons are found in numerous biologically active molecules and pharmaceuticals. 1-(1-Arylvinyl)pyridin-2(1H)-ones are synthetic intermediates derived from the enamide moiety, and only few examples of the synthesis of 1-(1-arylvinyl)-2-pyridones have been reported. In this work, a simple and efficient procedure for the synthesis of N-vinyl-substituted pyridones from ketones and 2-fluoropyridine in the presence of trifluoromethane sulfonic anhydride, followed by base treatment is described. Various ketones with electron-donating or -withdrawing groups at the benzene rings can be used in this reaction. A preliminary mechanistic study indicates that it is not very likely that both vinyl triflates and vinyl cations play major roles as intermediates in this transformation. The thus obtained pyridones can be subsequently transformed via C–H arylation and radical alkylation reactions.