Wavelength-dependent photolyses of 2,5-dichloro-3,6-bis(dialkylamino)-[1,4]benzoquinone

Photolysis of 2,5-dichloro-3,6-bis(dialkylamino)-[1,4]benzoquinone (1) at 254 nm or 300–500 nm produces the corresponding cyclized products (2) via the electron transfer-proton transfer sequence in a variety of solvents in quantitative yields within 10 min. In contrast, photolysis of 2,5-dichloro-3,6-bis(dialkylamino)-[1,4]benzoquinone (1) at >500 nm light source affords the elimination products (3) in good yields via the δ-hydrogen abstraction.