Fig. 1: Asymmetric acid-catalyzed photoreactions.
From: Chiral Brønsted acid-controlled intermolecular asymmetric [2 + 2] photocycloadditions
a Intramolecular [2 + 2] photocycloadditions via Lewis acid-catalyzed chromophore activation; LA = Lewis acid. b Intermolecular [2 + 2] photocycloadditions via Lewis acid-catalyzed triplet activation. c Intermolecular [2 + 2] photocycloadditions via Bronsted acid-catalyzed chromophore activation. HA = Brønsted acid.
