Mechanistic Studies on the Insertion of Carbonyl Substrates into Cu-H: Different Rate-Limiting Steps as a Function of Electrophilicity

Ba L. Tran, Benjamin D. Neisen, Amy L. Speelman, Thilina Gunasekara, Eric S. Wiedner, R. Morris Bullock

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

We report mechanistic studies on the insertion reactions of [(NHC)Cu(μ-H)]2 complexes with carbonyl substrates by UV-vis and 1H NMR spectroscopic kinetic studies, H/D isotopic labelling, and X-ray crystallography. The results of these comprehensive studies show that the insertion of Cu-H with an aldehyde, ketone, activated ester/amide, and unactivated amide consist of two different rate limiting steps: the formation of Cu-H monomer from Cu-H dimer for more electrophilic substrates, and hydride transfer from a transient Cu-H monomer for less electrophilic substrates. We also report spectroscopic and crystallographic characterization of rare Cu-hemiacetalate and Cu-hemiaminalate moieties from the insertion of an ester or amide into the Cu−H bond.

Original languageEnglish
Pages (from-to)8645-8653
Number of pages9
JournalAngewandte Chemie - International Edition
Volume59
Issue number22
DOIs
Publication statusPublished - May 25 2020

Keywords

  • Cu hydride
  • Cu-H hydride transfer
  • Cu-H monomerization
  • Cu-hemiaminalate
  • carbonyls

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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