Asymmetric catalysis of triplet-state photoreactions

For many decades, stereocontrol in triplet-state photoreactions was widely regarded an elusive goal. Catalytic strategies to influence the reactivity of transient electronically excited intermediates remains a significant challenge, but many distinctive molecular scaffolds are uniquely available through excited-state chemistry . This Chapter summarizes studies ranging from the first asymmetric photoisomerizations to recent developments in highly enantioselective photocycloaddition reactions.