The construction of four-membered rings via a 4-exo-dig cyclization was originally theorized to be unfavourable and only recently shown in sparse examples. Here the authors present a photochemical, radical 4-exo-dig cyclization of ynamides to form azetidines, promoted by copper photoredox catalysis.
- Clément Jacob
- Hajar Baguia
- Gwilherm Evano
