3,3-Dimethyl-1-phenyl-1-aza-3-silacyclopentane and 3,3,5-trimethyl-1-phenyl-1-aza-3-silacyclopentane were obtained by the reaction of dimethyl(chloromethyl)vinylsilane and dimethyl(chloromethyl)allylsilane with aniline in THF in the presence of mercury acetate followed by reduction with sodium borohydride. Aminomercuration-demercuration of dimethyl(3-chloropropyl)vinylsilane and dimethyl(3-chloropropyl)allylsilane results in the corresponding 3-chloropropylphenylaminoalkyl derivatives. Dimethyl(3-chloropropyl)(2-phenylaminopropyl)-silane undergoes cyclization under the same reaction conditions giving 2,4,4-trimethyl-1-phenyl-1-aza-4-silacycloheptane in low yield. Competitive nucleophilic substitution of the chloroalkyl group of initial silanes by aniline affords dimethyl(phenylaminoalkyl)alkenylsilanes.