Abstract: The photochemical decomposition of a-diazoamides leads to the intramolecular formation of lactams. Thus, the photolysis of N, N-diethyldiazoacetamide (1) in dioxane produces l-ethyl-4-methyl-2-azetidinone (2) and 1-ethyl-2-pyrollidinone (3) in roughly equal amounts. Striking solvent effects are observed on these reactions. As the polarity of the medium is increased, the ratio of@-lactamly-lactam increases. he gross effects of structure ...