Comparison of Decamethyldizincocene [(η<sup>5</sup>‑Cp*)<sub>2</sub>Zn<sub>2</sub>] versus Decamethylzincocene [Cp*<sub>2</sub>Zn] and Diethylzinc Et<sub>2</sub>Zn As Precatalysts for the Intermolecular Hydroamination Reaction

A comparison of the Zn–Zn bonded species [(η<sup>5</sup>-Cp*)<sub>2</sub>Zn<sub>2</sub>] versus the related organometallic zinc compound [Cp*<sub>2</sub>Zn] and ZnEt<sub>2</sub> for the intermolecular hydroamination reaction in the presence of equimolar amounts of [PhNMe<sub>2</sub>H]­[B­(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>] is reported. All compounds show high reaction rates under mild conditions and a good functional group tolerance for the addition of aniline derivatives to primary alkynes. Within this series the metallocene [Cp*<sub>2</sub>Zn] is the most active one, whereas the zinc–zinc bonded species [(η<sup>5</sup>-Cp*)<sub>2</sub>Zn<sub>2</sub>] shows the best selectivity. Most remarkable is the unexpected excellent catalytic performance of the zinc–zinc bonded species [(η<sup>5</sup>-Cp*)<sub>2</sub>Zn<sub>2</sub>].