Synthesis of N -Vinyl Cinnamaldehyde Nitrones through Atropisomeric Quinoxaline-Derived N , N , O -Ligand-Promoted Chan-Lam Reaction.

A type of quinoxaline-derived tridentate N , N , O -ligand was synthesized in good to excellent yields over three steps through iodination of 2-aryl indoles, sequential Kornblum-type oxidation with DMSO, and capture by 1,2-diaminobenzenes. The prepared atropisomeric N , N , O -ligand was successfully applied in the synthesis of N -vinyl cinnamaldehyde nitrones as only Z -isomers in good yields through the Chan-Lam reaction. The method features an easily accessed tunable tridentate N , N , O -ligand, broad substrate scope, good functional group tolerance, and high Z -isomer for N -vinyl nitrones.