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- Title
Copper‐Catalyzed C(sp<sup>3</sup>)−H Amidation: Sterically Driven Primary and Secondary C−H Site‐Selectivity.
- Authors
Bakhoda, Abolghasem (Gus); Jiang, Quan; Badiei, Yosra M.; Bertke, Jeffery A.; Cundari, Thomas R.; Warren, Timothy H.
- 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.
- Subjects
COPPER catalysts; AMIDATION; CARBON-hydrogen bonds; HYDROCARBONS; AZIDES
- Publication
Angewandte Chemie, 2019, Vol 131, Issue 11, p3459
- ISSN
0044-8249
- Publication type
Article
- DOI
10.1002/ange.201810556