H-1-NMR INVESTIGATION OF SI-ALKYLSUBSTITUTED 1,3,5-TRISILACYCLOHEXANES

Alkylsubstituted derivatives of 1,3,5-trisilacyclohexane have been pre pared and their H-1 NMR spectra recorded and analyzed. For the compoun d series 1-mono-, cis-1,3-di- and cis-cis-1,3,5-tri-alkylated derivati ves (alkyl = Me, Et, i-Pr and t-Bu) it is found that the conformationa l preference for an equatorial position of the substituents in the cha ir form is considerably less than for cyclohexane derivatives. In the compound Series trans-1,3-di- and cis-trans-1,3,5-tri-alkylated deriva tives the t-butyl group is found to behave uniqually by forcing the ri ng to escape into the twist-boat form. Each kind of substituent is fou nd to have a characteristic effect on the chemical shift values of the ring protons.