Synthesis and reactions of the first stable 1-germaallene

The first stable 1-germaallene was synthesized by treatment of an extremely hindered alkylidenetelluragermirane with a large excess amount of hexamethylphosphorous triamide or by reductive dechlorination of the corresponding overcrowded (1-chlorovinyl)chlorogermane with t-butyllithium in THF. The germaallene was isolated as a colorless solid by the latter synthetic method and found to be fairly stable even in solution at room temperature, although it underwent an intramolecular cyclization at 80 degrees C in benzene.