Inspired by the heme iron-catalyzed radical insertion of dioxygen to the tryptophan indole ring, herein we utilize alkylperoxy radical species as a coupling partner to trigger a peroxycyclization of readily accessible tryptophan derivatives and enable the first synthesis of peroxypyrroloindolenines. A preliminary biological evaluation revealed promising anti-cancer activities (IC50 = 22.00 μM for compound 2a), and revealed that both the indolenine core and the peroxy functionality are responsible for the antiproliferation effect against Hela cell lines.