Regioselective Synthesis of 6-Vinyl-3,6-dihydropyridine-2(1H)-ones through Simple Addition of a Vinylmagnesium Ate Complex to 2-Pyridones

A highly nucleophilic vinylation reagent, lithium vinyldimethylmagnesate (vinylMe(2)MgLi), is obtained by mixing vinylmagnesium chloride (1 equiv.) and MeLi (in diethoxymethane; 2 equiv.). The application of this new reagent in the completely regioselective synthesis of 6-vinyl-3,6-dihydro-1H-pyridin-2(1H)-ones by simple 1,6-additions to 2-pyridones is described. Examination of the scope and limitations of the addition revealed the influence on the efficiency of the 6-vinylation reaction of substituents on the nitrogen atom and on the 2-pyridone ring.