Selective Photochemical Continuous Flow Benzylic Monochlorination

A selective photochemical monochlorination of 2-fluorotoluene has been developed by a continuous flow process using two different flow reactors, one for the tuning of the conditions and the second one for the scale-up. The key reaction parameters were optimized using one-factor-at-a-time and design of experiment methods, with the goal of minimizing the formation of the dichlorinated by-product. This transformation has been performed on a multi decagram scale.