Cyclic and open-chain derivatives of bis(trihydrosilyl)benzenes

A series of 1,3-disila-isoindolines and -indans derived from 1,2-bis(trihydrosilyl)benzene have been prepared and spectroscopically characterised. The key intermediate for the preparation of the heterocycles is 1,2-bis(trifluoromethylsulfonyloxysilyl)benzene, obtained from 1,2-bis(p-tolylsilyl)benzene by treatment with 2 equivalents of triflic acid (CF₃SO₃H), at -10°C. Treatment of this intermediate with primary amines, or with H₂C=P(NMe₂)₃ in a transylidation process, afforded the heterocycles in high yields. The molecular structure of N-(p-bromophenyl)-1,3-disilaisoindoline has been determined by X-ray diffraction. The molecules are almost completely flat with only a minor curvature. Open-chain disiloxanes (m,p-H₃SiC₆H₄SiH₂)₂O were prepared from the corresponding arylsilyl(silyl)benzenes, which were converted into the trifluoromethylsulfonyloxysilyl-(silyl)benzenes (stable up to -10°C) by triflic acid and hydrolysed by water-NEt₃.