Cyclohexadienone photochemistry: chemical trapping and stereochemistry of the type A zwitterion
Abstract
Irradiation of 4-methyl-4-trichloromethylcyclohexa-2,5-dienone in the presence of cyclopentadiene gives two 1:1 adducts whose structures demonstrate the intermediacy of the type A zwitterion and whose stereochemistry shows that the walk rearrangement to the lumiketone proceeds with inversion of configuration.