Nickel-Catalyzed Direct Amination of Arenes with Alkylamines

Abstract

The efficient nickel-catalyzed direct amination of arenes with simple alkylamines has been achieved with the assistance of a bidentate directing group through sp(2) C-H bond functionalization. Preliminary mechanistic investigations indicate that the reaction probably proceeds through a Ni(I)/Ni(III) catalytic pathway.

A comprehensive overview of directing groups applied in metal-catalysed C–H functionalisation chemistry

“…Direct amination of arenecarboxamides was reported by Liu and Zhang using a Ni catalyst. 444 Being efficient (48–81% yield) with several secondary amines ( Scheme 73A ), this reaction provided mono-functionalised products and mechanistic studies suggested the involvement of a Ni I /Ni III catalytic cycle.…”

Direct Functionalization of C−H Bonds by Iron, Nickel, and Cobalt Catalysis

“…[61] The authors rationalized this on steric grounds. Additionally,t he ortho-amination reported by Liu and Zhang [60] towards 88 proceeds under air and is formally an oxidative process that, from the outset, appears mechanistically distinct from its counterparts.…”

“…Hammett plot experiments carriedo ut by Chatani furthers uggest that the reductive elimination might be rate-determining in the case of the arylation reaction. [62] While the oxidative aminationo fL iu and Zhang is dramatically inhibited by additives such as BHT (and an excesso fT EMPO), [60] leadingt hose authors to postulate aN i I /Ni III catalytic cycle, most of the other reportss ee little impact resulting from the addition of radicali nhibitors. The mechanisms proposed in those cases are more "conventional" Ni II /Ni IV oxidation state shuttles.…”

“…A string of publications rapidly followed, reporting a series of C−H functionalizations ortho to suitable disposed aromatic amide derivatives. These include alkynylation, arylation, alkylation, amination and thiolation . Scheme depicts selected examples that illustrate key transformations reported.…”

Directing‐Group‐Assisted Transition‐Metal‐Catalyzed Direct Intermolecular C−H Amidation and Amination of Arenes

“…Liu, Zhang et al . developed the first example of nickel‐catalyzed direct amination of arenes with simple alkylamines with the assistance of the 8‐aminoquinolyl auxiliary as a bidentate directing group (Scheme ).…”