Direct α-amination of nitrones achieved by DBU-activated N-haloimides. Issue 34 (24th August 2016)

• Record Type: Journal Article
• Authors: Li, Mengru; Liang, Fushun
• Is Part Of: Tetrahedron letters. Volume 57:Issue 34(2016)
• Page Start: 3823
• Page End: 3826
• Publication Date: 2016-08-24
• Subjects: Nitrones -- Quinoline N-oxides -- Amination -- NBS(P)-DBU -- Halogen bond activation; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2016.07.036
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: Direct α-amination of nitrones has been developed by using N -haloimide-DBU protocol. A halogen bond activation concept is proposed as the driving force for the amination. E / Z -Isomerization of α-aminonitrones is found to be related to acidic substances. A possible mechanism for the E / Z -isomerization process is depicted. Abstract: Direct α-amination of nitrones has been developed by using N -haloimide-DBU protocol. Reaction of nitrones with N -haloimide takes place readily in the presence of DBU in DCM, affording directly α-aminonitrones in moderate to excellent yields. N -Haloimide activated by DBU provides both a halogen cation and a nitrogen anion source. E - and Z -isomerization of α-aminonitrones was examined and found to be highly sensitive to acidic substances like silica gel and Brønsted acid. In addition to nitrones, quinoline N -oxides are also suitable substrates. Direct amination achieved by the protocol demonstrates new reactivity of nitrones and quinoline N -oxides.