Photo-induced 1,2-aryl migration of 2-chloro-1-arylpropanone under batch and flow conditions: Rapid, scalable and sustainable approach to 2-arylpropionic acids

We report the photo-mediated 1,2-aryl migration of 2-chloro-1-arylpropanones to 2-arylpropionic acids using HCOONa as an acid scavenger. This pragmatically focused study obviates the multiple-step sequence in the industrially employed, ZnO-promoted rearrangement strategy, and offers rapid access to various 2-arylpropionic acids under environmentally friendly conditions. Furthermore, the successful transfer of this batch photochemistry to a continuous flow platform led to improved scalability and enabled the gram-scale synthesis of loxoprofen.