Synthesis of Vinylgermanes via the Au/TiO2-Catalyzed cis-1,2-Digermylation of Alkynes and the Regioselective Hydrogermylation of Allenes.

In the presence of Au/TiO2 (1 mol %), terminal alkynes react quantitatively with stoichiometric amounts of the unactivated digermane Me3Ge-GeMe3, forming exclusively cis-1,2-digermylated alkenes. We also establish the Au/TiO2-catalyzed hydrogermylation of terminal allenes with Et3GeH, which exhibits a highly regioselective mode of addition on the more substituted double bond forming vinylgermanes. Additionally, we provide preliminary results regarding the Pd nanoparticle-catalyzed C-C coupling of 1,2-digermyl alkenes with aryl iodides.