Visible-Light-Induced Aza-Pinacol Rearrangement: Ring Expansion of Alkylidenecyclopropanes.

A novel visible-light-induced aza-pinacol rearrangement was developed for the first time. In this approach, the addition of the N-centered radical to the C═C bond of alkylidenecyclopropanes delivers a variety of cyclobutanimines and γ-butyrolactones, with all-carbon quaternary centers via the ring expansion of the cyclopropyl group, in moderate to good yields under mild reaction conditions.