In this report, the authors have clarified that the mu-oxo bridged heterocyclic hypervalent iodine compound 1 shows a more effective reactivity in the oxidative dearomatizing spirolactamization compared to conventional PIDA (phenyliodine(III) diacetate). Besides the high reactivity, a new selectivity during the oxidations based on the steric discrimination of the nitrogen groups of the pre-spirocyclic substrates is demonstrated for the heterocyclic hypervalent iodine compound 1.