A Facile Method for Multigram Scale Light-Induced Synthesis of 4′-(Bromomethyl)-2-cyanobiphenyl

A convenient, green method to synthesize 4′-(bromomethyl)-2-cyanobiphenyl was developed, where visible light is used to initiate the radical chain reaction and the H2O2/HBr system as the bromine source. A range of solvents was tested, and a final multigram protocol was developed to give a good yield of 71% of product with 97% purity and no other purification than simple filtration and wash. Diethyl carbonate was found to be an efficient greener solvent alternative to classical solvents such as carbon tetrachloride and chlorobenzene, and 2-propanol, also considered a green solvent, was suitable for precipitation and washing in the purification step.