Issue 47, 2021

Copper(ii) ketimides in sp3 C–H amination


Commercially available benzophenone imine (HN[double bond, length as m-dash]CPh2) reacts with β-diketiminato copper(II) tert-butoxide complexes [CuII]–OtBu to form isolable copper(II) ketimides [CuII]–N[double bond, length as m-dash]CPh2. Structural characterization of the three coordinate copper(II) ketimide [Me3NN]Cu–N[double bond, length as m-dash]CPh2 reveals a short Cu-Nketimide distance (1.700(2) Å) with a nearly linear Cu–N–C linkage (178.9(2)°). Copper(II) ketimides [CuII]–N[double bond, length as m-dash]CPh2 readily capture alkyl radicals R˙ (PhCH(˙)Me and Cy˙) to form the corresponding R–N[double bond, length as m-dash]CPh2 products in a process that competes with N–N coupling of copper(II) ketimides [CuII]–N[double bond, length as m-dash]CPh2 to form the azine Ph2C[double bond, length as m-dash]N–N[double bond, length as m-dash]CPh2. Copper(II) ketimides [CuII]–N[double bond, length as m-dash]CAr2 serve as intermediates in catalytic sp3 C–H amination of substrates R–H with ketimines HN[double bond, length as m-dash]CAr2 and tBuOOtBu as oxidant to form N-alkyl ketimines R–N[double bond, length as m-dash]CAr2. This protocol enables the use of unactivated sp3 C–H bonds to give R–N[double bond, length as m-dash]CAr2 products easily converted to primary amines R–NH2via simple acidic deprotection.

Graphical abstract: Copper(ii) ketimides in sp3 C–H amination

Supplementary files

Article information

Article type
Edge Article
09 Apr 2021
29 Oct 2021
First published
05 Nov 2021
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2021,12, 15733-15738

Copper(II) ketimides in sp3 C–H amination

I. U. Jayasooriya, A. (. Bakhoda, R. Palmer, K. Ng, N. L. Khachemoune, J. A. Bertke and T. H. Warren, Chem. Sci., 2021, 12, 15733 DOI: 10.1039/D1SC01990B

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