Realizing an Aza Paternò–Büchi Reaction

Intramolecular atropselective aza Paternò–Büchi reaction involving atropisomeric enamide and imine functionalities under sensitized irradiation leads to azetidine products in good yield and selectivity (ee >96 %). A mechanistic model based on detailed photophysical and isomerization kinetic studies is provided that shed light into the reactivity of enamides leading to aza Paternò–Büchi reaction. An intramolecular aza Paternò–Büchi reaction between atropisomeric enamide and imine functionalities under sensitized irradiation leads to azetidine products in good yields and high enantiomeric excess (see scheme). Detailed photophysical and isomerization kinetic studies shed light on the reaction mechanism.