Well-Defined β-Diketiminatocobalt(II) Complexes for Alkene Cyclohydroamination of Primary Amines

A well-defined low-coordinate β-diketiminatocobalt(II) alkyl complex is reported as an active precatalyst for the selective alkene cyclohydroamination of unprotected primary amines under mild conditions (rt–90 °C). The reaction mechanism has been investigated by deuterium-labeling, kinetics, and stoichiometric experiments and in-depth computational DFT studies. On the basis of these studies, we propose a stepwise noninsertive mechanism that features a rate-determining nucleophilic attack of the amido group of a monomeric cobalt(II) amidoalkene-aminoalkene adduct intermediate to the noncoordinated pendant alkene followed by a rapid proton transfer from the coordinated aminoalkene to the cyclized adduct.