Rhodium-Catalyzed Synthesis of Germoles via the Activation of Carbon–Germanium Bonds

The rhodium-catalyzed reaction of 2-germylphenylboronic esters with alkynes in the presence of a rhodium(I) catalyst is established as a modular method for the synthesis of an array of benzogermole derivatives. The reaction proceeds through the activation of C(sp³)–Ge bonds. The mechanism of this new bond activation process is discussed based on the activation aptitude of alkyl and aryl substituents on germanium.