RESUMO
A new protocol for the direct formation of amides from imines derived from aromatic aldehydes via metal-free aerobic oxidation in the presence of cyanide is described. This protocol was applicable to various aldimines, and the desired amides were obtained in moderate to good yields. Mechanistic studies suggested that this aerobic oxidative amidation might proceed via the addition of cyanide to imines followed by proton transfer from carbon to nitrogen in the original imines, leading to carbanions of α-amino nitriles, which undergo subsequent oxidation with molecular oxygen in air to provide the desired amide compounds.
RESUMO
A highly efficient synthesis of 2-aminoquinoxalines has been developed via the one-pot two-step cyanide-mediated sequential reactions of ortho-phenylenediamines with aldehydes under aerobic oxidation conditions. A variety of substrates, including aliphatic aldehydes bearing acidic α-protons, are applicable to this protocol and afford the desired 2-aminoquinoxalines in high yields.
