Solvent assisted photochemical formation of a new keto[3,3]paracyclophane

Photolysis of a phenacyl benzoate tethered with a phenol leads to a very efficient release of benzoic acid, which is suggested to occur by electron transfer and/or proton transfer from the remote phenol moiety to the triplet excited carbonyl. Photolysis of the compound in protic solvents forms a new keto[3,3]paracyclophane. Photolysis of a phenacyl photoremovable protecting group activated by covalently linked phenol in protic solvents forms a new keto[3,3]paracyclophane together with an efficient release of benzoic acid.