trans-Silylation of silatranes and 1,2-dimethyl-2-azasilatran-3-one by Si-substituted trimethoxysilanes

trans-Silylation of silatranes by Si-substituted trimethoxysilanes has been found to be a reversible reaction, the equilibrium of which is shifted towards the formation of the silatrane bearing a stronger (shorter) transannular N→Si bond. A related reaction of 1,2-dimethyl-2-azasilatran-3-one with Si-substituted trimethoxysilanes leads to products in good yields only when phenyltrimethoxysilane is used.