Arene C-H Amination with N -Heteroarenes by Catalytic DDQ Photocatalysis.

Arene C-H aminations using catalytic amounts of a 2,3-dichloro-5,6-dicyano- p -benzoquinone (DDQ) photocatalyst are described. Benzene, which has an oxidation potential of 2.48 V (vs SCE), was functionalized by pyrazoles, triazoles, tetrazoles, purines, and tert -butoxycarbonyl amine. Arenes underwent amination via a combination of ultraviolet (UV) light and a DDQ photocatalyst without a typical co-oxidant. Although the mechanism remains an open question, DDQH 2 , which is generated from DDQ after oxidation, is reactivated to DDQ under UV light irradiation conditions, possibly with the assistance of adventitious O 2 and/or a solvent as the terminal oxidant(s) in this system.