Quinone methide intermediates in organic photochemistry

Quinone methides are widely encountered reactive intermediates in the chemi stry of phenols and related compounds. This paper summarizes our recent pro gress in uncovering new and general photochemical methods for forming quino ne methides of various structural types in aqueous solution. Their mechanis m of formation and subsequent chemistry are also discussed. New examples of excited-state intramolecular proton transfer (ESIPT) have been uncovered i n these studies. We have also discovered that appropriately designed biphen yls and terphenyls display photochemistry that is best rationalized by high ly polarized and planar excited states of these ring systems, which can eff iciently lead to the corresponding extended quinone methides.