A copper-promoted intramolecular C-H oxidative amination reaction between secondary amine (N-H) and C(sp3)-H at the benzylic position of azaarenes or α-position of ketones for the synthesis of aziridine derivatives has been developed. Moreover, a practical annulation of electron-deficient vinylarenes with an unprotected primary alkyl amine by a Yb(OTf)3-CuI relay system has also been reported. The reactions were carried out with oxygen as the sole oxidant to give the N-alkyl- and N-arylaziridines in good yields.