One-pot chlorocarboxylation of toluenes with chlorine dioxide under photoirradiation.

Chlorocarboxylation of toluene was achieved by photoirradiation of a chlorine dioxide radical (ClO 2 ˙) under ambient conditions (298 K and 1 atm). 2- and 4-Chlorobenzoic acids were obtained in a 1 : 1 yield ratio. This is a single step synthesis under metal-free and mild conditions.