Comparison of Decamethyldizincocene [(η⁵‑Cp*)₂Zn₂] versus Decamethylzincocene [Cp*₂Zn] and Diethylzinc Et₂Zn As Precatalysts for the Intermolecular Hydroamination Reaction

Abstract

A comparison of the Zn–Zn bonded species [(η⁵-Cp*)₂Zn₂] versus the related organometallic zinc compound [Cp*₂Zn] and ZnEt₂ for the intermolecular hydroamination reaction in the presence of equimolar amounts of [PhNMe₂H]­[B­(C₆F₅)₄] 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*₂Zn] is the most active one, whereas the zinc–zinc bonded species [(η⁵-Cp*)₂Zn₂] shows the best selectivity. Most remarkable is the unexpected excellent catalytic performance of the zinc–zinc bonded species [(η⁵-Cp*)₂Zn₂]