Flash Communication: Reversible O–H Bond Activation at a Bicyclic Germanide via Ge-Ligand Cooperativity

Low-valent germanium compounds, such as germylenes, can undergo a variety of activation reactions, but the development of related catalytic processes is hindered by a challenging reductive elimination step. A possible way to overcome this obstacle is element-ligand cooperativity (ELC), which allows generation of reactive species without an oxidation state change at the element center. Here, we report the reactivity of the bicyclic germanide K[(tmim)Ge] (tmimH3 = tris(3-methylindol-2-yl)methane) with a phenolic O–H bonds which, instead of formal oxidative addition, undergoes a reversible O–H addition reaction coupled with cage opening to generate a Ge(II) phenoxide via element-ligand cooperativity.