Basic Reactivity Pattern of a Cyclic Disilylated Germylene

In order to estimate
the reactivity of disilylated germylene phosphine
adducts, a cyclic version of this compound class was reacted with
a number of different reagents. Reactions with the chalcogens sulfur,
selenium, and tellurium led to dimers of the heavy ketone analogues.
Reactions with water and ethyl bromide proceeded to give the respective
oxidized germanol and germyl bromide. Two different reactions with
alkynes were observed which led either to a germacyclopropene, by
addition of tolane to the germylene, or to a silagermacyclobutene,
likely formed by addition of the alkyne across a silagermene. Reaction
via the silagermene was also observed in the reaction with benzophenone.
Reaction of a germylene phosphine adduct with GeCl2·(dioxane)
provided insertion of the silylated germylene into a Ge–Cl
bond, leading to a germylated chlorogermylene phosphine adduct.