Reactions of group IV organometallic compounds. Part XIX. Substituent effects on the rate of trimethylsilyl migration in substituted NO-bis(trimethylsilyl)benzimidates

Abstract

The rate of interconversion of the trimethylsilyl group in five para-substituted NO-bis(trimethylsilyl)benzimidates was determined by means of n.m.r. spectrometry in trichloroethylene. Electron-donating substituents on the aryl group were found to favour the intramolecular transfer of the trimethylsilyl group with Hammett's ρ=– 1·05. Interconversion of trimethylsilyl groups in NO-bis(trimethylsilyl)benzimidates therefore occurred through the corresponding NN-bis(trimethylsilyl)benzamides.