@article{2928852,
    title = "A Versatile Tripodal Cu(I) Reagent for C–N Bond Construction via Nitrene-Transfer Chemistry: Catalytic Perspectives and Mechanistic Insights on C–H Aminations/Amidinations and Olefin Aziridinations",
    author = "Vivek Bagchi and Patrina Paraskevopoulou and Purak Das and Lingyu Chi and Qiuwen Wang and Amitava Choudhury and Jennifer S. Mathieson and Leroy Cronin and Daniel B. Pardue and Thomas R. Cundari and George Mitrikas and Yiannis Sanakis and Pericles Stavropoulos",
    journal = "Journal of the American Chemical Society",
    year = "2014",
    volume = "136",
    number = "32",
    pages = "11362--11381",
    publisher = "American Chemical Society (ACS)",
    issn = "0002-7863, 1520-5126",
    doi = "10.1021/ja503869j",
    abstract = "A Cu-I catalyst (1), supported by a framework of strongly basic
guanidinato moieties, mediates nitrene-transfer from PhI=NR sources to a
wide variety of aliphatic hydrocarbons (C-H amination or amidination in
the presence of nitriles) and olefins (aziridination). Product profiles
are consistent with a stepwise rather than concerted C-N bond formation.
Mechanistic investigations with the aid of Hammett plots, kinetic
isotope effects, labeled stereochemical probes, and radical traps and
clocks allow us to conclude that carboradical intermediates play a major
role and are generated by hydrogen-atom abstraction from substrate C-H
bonds or initial nitrene-addition to one of the olefinic carbons.
Subsequent processes include solvent-caged radical recombination to
afford the major amination and aziridination products but also
one-electron oxidation of diffusively free carboradicals to generate
amidination products due to carbocation participation. Analyses of
metal- and ligand-centered events by variable temperature electrospray
mass spectrometry, cyclic voltammetry, and electron paramagnetic
resonance spectroscopy, coupled with computational studies, indicate
that an active, but still elusive, copper-nitrene (S = 1) intermediate
initially abstracts a hydrogen atom from, or adds nitrene to, C-H and
C=C bonds, respectively, followed by a spin flip and radical rebound to
afford intra- and intermolecular C-N containing products."
}