Suzuki M, Terada M, Nakamura I. Copper-catalyzed [1,3]-nitrogen rearrangement of
O-aryl ketoximes
via oxidative addition of N–O bond in inverse electron flow
†.
Chem Sci 2023;
14:5705-5711. [PMCID:
PMC10231427 DOI:
10.1039/d3sc00874f]
[Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/28/2023] [Indexed: 06/01/2023] Open
Abstract
The [1,3]-nitrogen rearrangement reactions of O-aryl ketoximes were promoted by N-heterocyclic carbene (NHC)-copper catalysts and BF3·OEt2 as an additive, affording ortho-aminophenol derivatives in good yields. The reaction of substrates with electron-withdrawing substituents on the phenol moiety are accelerated by adding silver salt and modifying the substituent at the nitrogen atom. Density functional theory calculations suggest that the rate-determining step of this reaction is the oxidative addition of the N–O bond of the substrate to the copper catalyst. The negative ρ values of the substituent at both the oxime carbon and phenoxy group indicate that the donation of electrons by the oxygen and nitrogen atoms accelerates the oxidative addition.
[1,3]-Nitrogen rearrangement reactions of O-aryl ketoximes was catalytically promoted by IPrCuBr and BF3·OEt2. The oxidative addition of the N–O bond to the Cu catalyst is accelerated by donation of electrons from both nitrogen and oxygen atoms.![]()
Collapse