Silicon-containing dimethylphosphoric acid amides

α-Silylmethylamines MeNHCH2SiMen(OMe)3−n (n=0, 2) were involved into Todd-Atherton reaction with (MeO)2P(O)H giving N-methyl-N-trimethoxysilylmethyl-and N-methyl-N-dimethyl-(methoxy)silylmethylamides of dimethylphosphoric acid. A reaction of these compounds with BF3·Et2O led to the formation of the corresponding N-methyl-N-trifluoro-and N-methyl-N-(dimethyl)fluorosilylmethylamides of dimethylphosphoric acid. (MeO)2P(O)N(Me)CH2SiF3 existed as an (O-Si)-chelate with a pentacoordinate silicon due to the occurrence of a rare and unstudied intramolecular coordinating interaction P=O → Si.