In our pursuit to elucidate the mechanism, we executed a series of experiments to explore the radical pathway and identify the catalytic species facilitating the photochemical transformation. Confirmation of the radical nature of the reaction was achieved through radical trapping and radical clock experiments (Figure ). Indeed, ESI-HRMS analysis substantiated the formation of TEMPO adduct 62, while GC-MS analysis convincingly demonstrated carbon radical formation through the production of 64 via a 5-exo-trig radical cyclization.