Additionsreaktionen an intramolekular basenstabilisierte Ge=N- und Ge=S-Doppelbindungen

Abstract

The GeN bond of 1 adds hydrogen chloride, ethanol, tert-butyl alcohol, methyllithium, and methyl iodide to form 3-6 and 8. The GeS bond in 2 analogously adds methyl iodide to yield 10. In the resulting products the electropositive part of the polar reactand is bound to nitrogen or sulfur, while the electronegative one is on the germanium atom. In the lithium derivative 6 and in the iodine derivative 8 Li and I can be replaced by hydrogen to form two isomers of the same composition 7 and 9, which differ only in the positions of the hydrogen and methyl groups with respect to Ge or N. The X-ray structure analyses on 4, 9, and 10 reveal that the germanium atom is fourfold coordinated by two nitrogen atoms and two other ligands. The intramolecular nitrogen base of the silazyl moiety in 1 and 2 is, thus, expelled from the coordination sphere of germanium by insertion of the double bonds into polar bonds, and the tricyclic molecule is changed to a bicyclic one. Thus these base stabilized bonds in 1 and 2 behave as normal unsaturated systems.