Novel photoinduced self-substitution of 2,5-dichloro-1,4-benzoquinone

Abstract

2,5-Dichloro-1,4-benzoquinone (DCBQ) undergoes self-substitution to 1,4-bis(4-chloro-3,6-dioxocyclohexa-1,4-dienyloxy)-2,5-dichlorobenzene (BDB) and 2,5-bis[4-(4-chloro-3,6-dioxocyclohexa-1,4-dienyloxy)-2,5-dichlorophenoxy]benzoquinone (BBQ) in the presence of N,N-dimethyl-tert-butylamine (DMBA) or N,N-dimethyl-4-phenylbicyclo[2.2.2]octan-1-ylamine (DMPA) in sunlight; photo-CIDNP studies show that the reaction is initiated by photoinduced electron transfer between DCBQ and the amine with the triplet radical ion pair as the intermediate.