Photo-Induced Hydrogen Abstraction and Addition Reactions of Aromatic Compounds

4 Photo-Induced Hydrogen Abstraction and Addition Reactions of Aromatic Compounds 

Photoexcited aromatic hydrocarbons undergo hydrogen abstraction and 1,4-addition reactions with cycloalkanes and hydroxylic compounds. These reactions are believed to take place through an excited singlet state of arene to form an exciplex or ion pair as an intermediate, which on back electron transfer dissociates into triplet diradical and undergoes proton abstraction from solvent or amines, followed by addition of an alkyl or aryl unit to give the products [37]. The following examples of this reaction are illustrative  

In entry 4, the reaction proceeds through a prefitlvene diradical intermediate. 

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