Photolysis of bis(2,3-diphenylcycloprop-2-enyl)methane resulted in a novel intramolecular[:! + 21 -cycloaddition followed by a facile cycloreversion of the initially-produced quadricyclane to give tetraphenylbicyclo [2.2.1] ... Photochemical syntheses of strained polycyclic molecules and their catalytic cycloreversions have attracted considerable attention in recent years as possible models for light-energy storage systems.l Among the criteria important for an efficient ...