Ir-Catalyzed Intermolecular Branch-Selective Allylic C–H Amidation of Unactivated Terminal Olefins

Abstract

An efficient method for intermolecular branch-selective allylic C-H amidation has been accomplished via Ir(III) catalysis. The reaction proceeds through initial allylic C-H activation, supported by the isolation and crystallographic characterization of an allyl-Ir(III) intermediate, followed by a subsequent oxidative amidation with readily available dioxazolones as nitrenoid precursors. A diverse range of amides are successfully installed at the branched position of terminal alkenes in good yields and regioselectivities. Importantly, the reaction allows the use of amide-derived nitrenoid precursors avoiding problematic Curtius-type rearrangements.

An Update of Transition Metal-Catalyzed Decarboxylative Transformations of Cyclic Carbonates and Carbamates

“…The reactions could be carried out under mild conditions and tolerated well with different functionalities [59]. Regioselective amidation of allylic alkenes involving inert C-H activation with the use of 1,4,2-Dioxazol-5-ones as starting materials was also feasible utilizing Ir or Rh catalyst [60][61][62]. As analogs of cyclic carbamates, isatoic anhydrides have also emerged as powerful building blocks for the preparation of functionalized N-heterocycles.…”

Intermolecular, Branch‐Selective, and Redox‐Neutral Cp*IrIII‐Catalyzed Allylic C−H Amidation

“…Theu tilization of internal olefins and complex dioxazolones are complementary results to af undamental work by Rovis that appeared just prior to submission of this manuscript. [17] We then investigated the reaction mechanism. Considering that Ir-nitrenoid species are known to undergo CÀH insertion, [4,11,18] we envisaged two mechanistic pathways: 1) proceeding via C À Ha ctivation and the formation of am etal-allyl species,o r2 )the direct insertion of am etalnitrenoid species into the allyllic CÀHb ond (Scheme 4).…”

Intermolecular 1,4‐Carboamination of Conjugated Dienes Enabled by Cp*RhIII‐Catalyzed C−H Activation

“…To address these challenges,weenvisioned that we could form aR h III -allyl species upon insertion of ad iene into aRh III À Cbond generated by C À Hactivation. [14] We hypothe-sized that the additional coordination of the alkene would prevent b-H elimination in order that this species could then be coupled with an electrophilic amination reagent, such as ad ioxazolone, [15] to deliver the protected primary amine product (Scheme 1B).…”