Copper(ii) ketimides in sp 3 C-H amination.

Commercially available benzophenone imine (HN[double bond, length as m-dash]CPh 2 ) reacts with β-diketiminato copper(ii) tert -butoxide complexes [Cu II ]-O t Bu to form isolable copper(ii) ketimides [Cu II ]-N[double bond, length as m-dash]CPh 2 . Structural characterization of the three coordinate copper(ii) ketimide [Me 3 NN]Cu-N[double bond, length as m-dash]CPh 2 reveals a short Cu-N ketimide distance (1.700(2) Å) with a nearly linear Cu-N-C linkage (178.9(2)°). Copper(ii) ketimides [Cu II ]-N[double bond, length as m-dash]CPh 2 readily capture alkyl radicals R˙ (PhCH(˙)Me and Cy˙) to form the corresponding R-N[double bond, length as m-dash]CPh 2 products in a process that competes with N-N coupling of copper(ii) ketimides [Cu II ]-N[double bond, length as m-dash]CPh 2 to form the azine Ph 2 C[double bond, length as m-dash]N-N[double bond, length as m-dash]CPh 2 . Copper(ii) ketimides [Cu II ]-N[double bond, length as m-dash]CAr 2 serve as intermediates in catalytic sp 3 C-H amination of substrates R-H with ketimines HN[double bond, length as m-dash]CAr 2 and t BuOO t Bu as oxidant to form N -alkyl ketimines R-N[double bond, length as m-dash]CAr 2 . This protocol enables the use of unactivated sp 3 C-H bonds to give R-N[double bond, length as m-dash]CAr 2 products easily converted to primary amines R-NH 2 via simple acidic deprotection.