Copper(ii) ketimides in sp3C-H amination

Abstract

Commercially available benzophenone imine (HNCPh2) reacts with β-diketiminato copper(ii) tert-butoxide complexes [CuII]-OtBu to form isolable copper(ii) ketimides [CuII]-NCPh2. Structural characterization of the three coordinate copper(ii) ketimide [Me3NN]Cu-NCPh2 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]-NCPh2 readily capture alkyl radicals R (PhCH()Me and Cy) to form the corresponding R-NCPh2 products in a process that competes with N-N coupling of copper(ii) ketimides [CuII]-NCPh2 to form the azine Ph2CN-NCPh2. Copper(ii) ketimides [CuII]-NCAr2 serve as intermediates in catalytic sp3 C-H amination of substrates R-H with ketimines HNCAr2 and tBuOOtBu as oxidant to form N-alkyl ketimines R-NCAr2. This protocol enables the use of unactivated sp3 C-H bonds to give R-NCAr2 products easily converted to primary amines R-NH2via simple acidic deprotection. This journal is