Regioselective chelation in the reaction of N-trimethylsilyl-N-acetylglycine N’,N’-dimethylamide with chloro(chloromethyl)dimethylsilane

Regioselective reaction of N-trimethylsilyl-N-acetylglycine N’,N’-dimethylamide with chloro(chloromethyl)dimethylsilane yields chlorosilane MeC(O)N(CH₂SiMe₂Cl)CH₂C(O)NMe₂ with a five-membered C,O-chelate ring involving the N-acetyl group rather than the six-membered ring involving the N’,N’-dimethylamide fragment. According to X-ray data, the pentacoordinate silicon atom in the product has a TBP environment with the halogen and oxygen atoms in axial positions.