The lithiation of brominated aryl (alpha-dimethylsilyl)alkyl sulfides in diethyl ether produces stable heterocyclic silanes, which were characterized by H-1, C-13, and Si-29 NMR spectroscopy and by X-ray crystallography. The reaction involves the intramolecular attack of the phenyl carbanion on the silicon atom with the formation of a pentacoordinated silicon intermediate. The stability of the formed intermediate depends on the solvent. It decomposes easily in THF at -78 degrees C with Si-C bond cleavage; however, it is stable in diethyl ether at room temperature. Addition of water results in the Si-H bond cleavage, while the heterocyclic ring containing the silicon atom is conserved.