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Bis(trimethylsilyl)ketene acetals react with pyridines, quinoline and isoquinoline in the presence of stoichiometric amounts of methyl chloroformate to give the corresponding dihydropyridine-, dihydroquinoline-and dihydroisoquinoline-substituted carboxylic acids in satisfactory yields. The regio-and diastereoselectivities of the addition reactions, together with the presence or absence of rotamers, have been established. The isolated acids react with peracids to give β-hydroxy-δ-lactones through an intramolecular reaction. Similar lactonizations could also be brought about directly from the azaaromatic compounds in one-pot reactions with silica