4-Alkylpyridines are converted to conjugated 1,1-disubstituted alkenyl pyridines (vinyl pyridines) upon treatment with excess ethyl chloroformate, triethylamine, and Eschenmoser’s salt. The reaction proceeds under mild conditions via alkylidene dihydropyridine intermediates

4-Picoline derivatives are converted to the corresponding aryl picolyl sulfones upon treatment with aryl sulfonyl chlorides and Et 3 N in the presence of catalytic DMAP. The reaction proceeds smoothly for a variety of alkyl and aryl picolines using a range of aryl sulfonyl chlorides. The reaction is believed to involve N-sulfonyl 4alkylidene dihydropyridine intermediates and results in formal sulfonylation of unactivated picolyl C−H bonds.

An experimentally simple one-pot preparation of N -alkenyl-2-pyridones is reported. The reaction features mild conditions using readily available 2-halopyridinium salts and aldehydes. N -Alkenyl-2-pyridone formation proceeds with high diastereoselectivity, and a wide range of aldehyde reaction partners is tolerated. Pyridone products are also amenable to further manipulation, including conversion to N -alkyl pyridones and polycyclic ring systems.

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