TRANS-disubstituted γ-lactams was developed, consisting of the radical cyclization of cinnam-amides mediated by cerium(IV) ammoniumnitrate. The single-electron-transfer (SET) reaction of the methoxystyrenyl moiety mediated by cerium(IV) ammoniumnitrate gives rise to a cation radical, whose cyclization followed by reaction with oxygen and methanol generates 3,4- TRANS-disubstituted γ-lactams.