Copper(ii) ketimides in sp3 C–H amination. Issue 47 (24th November 2021)

• Record Type: Journal Article
• Authors: Jayasooriya, Isuri U.; Bakhoda, Abolghasem (Gus); Palmer, Rachel; Ng, Kristi; Khachemoune, Nour L.; Bertke, Jeffery A.; Warren, Timothy H.
• Is Part Of: Chemical science. Volume 12:Issue 47(2021)
• Page Start: 15733
• Page End: 15738
• Publication Date: 2021-11-24
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d1sc01990b
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Commercially available benzophenone imine (HNCPh2 ) reacts with β-diketiminato copper(ii ) tert -butoxide complexes [Cu II ]–O t Bu to form isolable copper(ii ) ketimides [Cu II ]–NCPh2 that serve as intermediates in catalytic sp 3 C−H amination via radical relay. Abstract : Commercially available benzophenone imine (HNCPh2 ) reacts with β-diketiminato copper(ii ) tert -butoxide complexes [Cu II ]–O t Bu to form isolable copper(ii ) ketimides [Cu II ]–NCPh2 . Structural characterization of the three coordinate copper(ii ) ketimide [Me3 NN]Cu–N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 [Cu II ]–NCPh2 readily capture alkyl radicals R˙ (PhCH(˙)Me and Cy˙) to form the corresponding R–NCPh2 products in a process that competes with N–N coupling of copper(ii ) ketimides [Cu II ]–NCPh2 to form the azine Ph2 CN–NCPh2 . Copper(ii ) ketimides [Cu II ]–NCAr2 serve as intermediates in catalytic sp 3 C–H amination of substrates R–H with ketimines HNCAr2 and t BuOO t Bu as oxidant to form N -alkyl ketimines R–NCAr2 . This protocol enables the use of unactivated sp 3 C–H bonds to give R–NCAr2 products easily converted to primary amines R–NH2 via simple acidic deprotection.