Mannich reaction of ketones using 1,3-dioxolane instead of formaldehyd
e, paraformaldehyde, or 1,3,5-trioxane afforded the corresponding Mann
ich bases in high yields. Under the same conditions the aminomethylati
on of aromatics did not proceed but the intramolecular aminomethylatio
n, like a Pictet-Spengler type reaction, proceeded smoothly.