Gold-Catalyzed C-H Functionalization with Aryl Germanes

The development of orthogonal C-sp(2)-C-sp(2) coupling regimes to the omnipresent Pd-catalysis class would enable an additional dimension of modularity in the construction of densely functionalized biaryl motifs. In this context, the identification of potent functional groups for selective transformations is in high demand. Although organogermanium compounds are generally believed to be of low reactivity in homogenous catalysis, this report discloses the highly efficient and orthogonal reactivity of aryl germanes with arenes under gold catalysis. The method is characterized by mildness, the employment of an air- and moisture-stable gold catalyst, and robustness. Our mechanistic studies show that aryl germanes are highly reactive with Au-(I) and Au-(III). Our computational data suggest that the origin of this reactivity primarily lies in the relatively low bond dissociation energy and as such low distortion energy to reach the key bond activating transition state.