Iridium‐Catalyzed Hydroamination

[Ir(COD)Cl]2 as a Catalyst Precursor for the Intramolecular Hydroamination of Unactivated Alkenes with Primary Amines and Secondary Alkyl- or Arylamines: A Combined Catalytic, Mechanistic, and Computational Investigation

“…In the case of late metal-mediated transformations these include (but are not restricted to) processes involving: nucleophilic attack of an amine on a metal-coordinated alkene, ,, an η 3 -allyl or related complex, or an η 6 -vinylarene complex; N−H bond activation followed by alkene insertion into an M-NR 2 linkage; − amine coordination followed by proton-transfer to an activated alkene; and nucleophilic attack of a metal amido species on an activated alkene . While experimental evidence for Ir-mediated N−H bond activation/alkene insertion reaction sequences has been obtained for the intermolecular hydroamination of activated alkenes such as norbornene, − mechanistic experiments indicate that the Ir-catalyzed intramolecular hydroamination (and hydroalkoxylation) of alkynes can proceed via alternative reaction pathways involving alkyne activation/nucleophilic attack. , However, a thorough kinetic analysis of the late metal-mediated cyclohydroamination of unactivated alkenes with secondary alkyl- or arylamines has yet to appear in the literature. In an effort to gain insight into the mechanism of such transformations, so as to guide the development of increasingly effective catalysts, a kinetic examination of the [Ir(COD)Cl] 2 -mediated hydroamination reactions featured herein was conducted.…”

“…We provide herein a complete account of our studies using [Ir(COD)Cl] 2 as a precatalyst for the intramolecular addition of primary as well as secondary alkyl- or arylamines to unactivated olefins . Mechanistic investigations of these intramolecular hydroamination reactions employing a combination of experimental and computational techniques reveal that such transformations proceed via an olefin activation mechanism that had previously not been documented for Ir-catalyzed alkene hydroamination. − …”

“…Encouraged by advances in the Ir-mediated intermolecular hydroamination of activated alkenes, − as well as recent progress in the Ir-catalyzed cyclohydroamination of alkynes, , we sought to expand further the synthetic repertoire of late metal-mediated hydroamination through the identification of simple Ir precatalysts that exhibit useful substrate scope in the intramolecular hydroamination of unactivated olefins. We provide herein a complete account of our studies using [Ir(COD)Cl] 2 as a precatalyst for the intramolecular addition of primary as well as secondary alkyl- or arylamines to unactivated olefins .…”

Enantiopure Amidinate Complexes of the Rare-Earth Elements

“…For a larger number of metals hydroamination catalysts have been developed. The progress in this area over the past decade has been reviewed extensively. − The enantioselective hydroamination reaction catalyzed by metallocene complexes of the rare-earth elements was pioneered in the 1990s by Marks and co-workers ,− and has then been extended to nonmetallocene rare-earth-element catalysts . Parallel to this development, enantioselective catalysts based on other metals have also been reported. ,− However, there is still a great demand for catalysts that can enantioselectively transform a broad range of substrates at moderate temperatures with low catalyst loadings.…”

Addition of N–H bonds to iridium: Synthesis and characterization of N–Ir–H complexes and the observation that an iridium N-bonded indole ring becomes activated for Michael addition to alkynes

“…Examples of catalytic amination based on oxidative addition of a N-H bond followed by an insertion-reductive elimination sequence have been reported. More recent attention to N-H activation has increased [13][14][15][16][17][18][19][20][21].…”