Enhanced nucleophilicity of ambiphilic silylene and silylenoid bearing 8-(dimethylamino)-1-naphthyl group

Some new aspects of intramolecularly amine-coordinated silylenes, ammonium silaylide, and amine-coordinated magnesium (chloro)silylenoids are summarized. The divalent silicon species bearing the 8-(dimethylamino)-1-naphthyl group, generated by the thermal degradation of a pseudo-pentacoordinated ethoxy- or fluoro-disilane, behaves as a nucleophilic ammonium silaylide as well as the amine-coordinated silylene, whose electrophilic character is weakened in comparison with that of free silylenes in some reactions in the presence of trapping agents such as 1,3-diene, diphenyl acetylene (in the absence or presence of water), and phenylacetylene, and in the absence of any trapping agent. The amine-coordinated silylenoid also behaves as an ambiphile, but the reaction courses are different from those observed with the amine-coordinated silylene and silaylide. A novel amino-group migration from naphthyl carbon to silicon has been observed in both species.