Selective Photoredox Direct Arylations of Aryl Bromides in Water in Microfluidic Reactor

Carrying out photoredox direct arylation couplings between aryl halides and aryls in water solution of surfactants enables unprecedented selectivity with respect to the competing dehalogenation process, thanks to the partition coefficient of selected sacrificial base. The use of a microfluidic reactor dramatically improves reaction time, without eroding yields and selectivity. The designs of a metal free sensitizer which also acts as the surfactant sizeably improves the overall sustainability of arylation reactions and removes the need for troublesome purification from traces of metal catalysts. The generality of the method is investigated over a range of halides carrying a selection of electron withdrawing and electron donating substituents.