Fig. 1: Background and an intermolecular aza Paternò–Büchi reaction using sulfamoyl fluoride imines.

a, Examples of pharmaceutically relevant azetidines. b, Retrosynthetic analysis of azetidines and the aza Paternò–Büchi reaction. c, Established alternative modes of reactivity for imine derived triplet intermediates. d,e, Prior art for intermolecular aza Paternò–Büchi reactions using cyclic imines (d) and using excitable alkenes (e). f, Model system for study (DFT method: SMD(1,2-dichloroethane)-M06-2X-D3/def2-TZVP in kcal mol−1). g, Preliminary results for the development of an intermolecular aza Paternò–Büchi reaction. ISC, intersystem crossing.