Cobalt-Catalyzed C(sp2)–H/C(sp3)–H Coupling via Directed C– H Activation and 1,5-Hydrogen Atom Transfer

Abstract

A cobalt-catalyzed C(sp2)–H/C(sp3)–H coupling reaction between an aryl imine and a 2-bromobenzyl-protected secondary amine is reported. Promoted by a combination of a cobalt–N-heterocyclic carbene catalyst and a Grignard reagent, the reaction allows for the introduction of α-aminoalkyl groups into the ortho position of the imine at a mild temperature. The cobalt catalyst is proposed to play key roles in two distinct modes of C–H cleavage, i.e., directed C–H metalation and 1,5-hydrogen atom transfer (HAT).

Publication
Sun, Q.; Yoshikai, N. Org. Chem. Front. 2018, 5, 582-585.