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Abstract Undirected C(sp3)−H functionalization reactions often follow site‐selectivity patterns that mirror the corresponding C−H bond dissociation energies (BDEs). This often results in the functionalization of weaker tertiary C−H bonds in the presence of stronger secondary and primary bonds. An important, contemporary challenge is the development of catalyst systems capable of selectively functionalizing stronger primary and secondary C−H bonds over tertiary and benzylic C−H sites. Herein, we report a Cu catalyst that exhibits a high degree of primary and secondary over tertiary C−H bond selectivity in the amidation of linear and cyclic hydrocarbons with aroyl azides ArC(O)N3. Mechanistic and DFT studies indicate that C−H amidation involves H‐atom abstraction from R‐H substrates by nitrene intermediates [Cu](κ2‐N,O‐NC(O)Ar) to provide carbon‐based radicals R.and copper(II)amide intermediates [CuII]‐NHC(O)Ar that subsequently capture radicals R.to form products R‐NHC(O)Ar. These studies reveal important catalyst features required to achieve primary and secondary C−H amidation selectivity in the absence of directing groups.
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Probing Redox Non‐Innocence in Iron–Carbene Complexes {Fe=C(H)Ar} 10–11 by 1,2 H and 13 C Pulse Electron Paramagnetic Resonance
Abstract We report the synthesis and spectroscopic characterization of a series of iron‐carbene complexes in redox states {Fe=C(H)Ar}10–11. Pulse EPR studies of the1,2H and13C isotopologues of {Fe=C(H)Ar}11reveal the high covalency of the Fe–carbene bonding, leading to a more even spin distribution than commonly observed for reduced Fischer carbenes.
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- Award ID(s):
- 1905320
- PAR ID:
- 10302559
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 60
- Issue:
- 52
- ISSN:
- 1433-7851
- Format(s):
- Medium: X Size: p. 27220-27224
- Size(s):
- p. 27220-27224
- Sponsoring Org:
- National Science Foundation
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