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.