Abstract In a study of the interaction of ketene with mono-or dialkylaminosilanes a number of new rearrangements was observed. When acted upon by ketene, dialkylaminosilanes, depending on the conditions applied, produce either amides of β-siloxyvinylacetic acid (I)(route “a”, scheme A) or amides of silylated acetic acid (II)(routes “b”,“c”). In both cases an intermediate α-siloxyvinyldialkylamine (III) was isolated which may be rearranged to give ...