Cyclization of N-methyl-3, 4-dimethoxyphenylacetamide (1) with paraformaldehyde in formic acid afforded 6, 7-dimethoxy-3-isochromanone (2b). In contrast, the same reaction of α, α-disubstituted phenylacetamides (5a, b, d) gave the corresponding 4, 4-disubstituted isoquinolin-3-ones (7a-c). However, the α-allylphenylacetamide (5c) gave the azepinone (8) as the main product. On the other hand, the carbamate (6e) afforded the 4-allylisoquinoline (10).