Synthesis of N-Alkylpyridin-4-ones and Thiazolo[3,2-a]pyridin-5-ones Through Pummerer-Type Reactions

N-alkylated 4-pyridones were obtained through a one-pot procedure involving either normal or interrupted Pummerer reactions between triflic anhydride activated sulfoxides and 4-fluoropyridine derivatives, followed by hydrolysis. On the other hand, triflic anhydride activated benzyl 6-fluoro-2-pyridyl sulfoxide could react with alkenes or alkynes to afford thiazolo[3,2-a]pyridin-5-ones, via the pyridinium salt intermediates.