Visible-light-mediated photochemistry: accelerating Ru(bpy)32+-catalyzed reactions in continuous flow

The first application of visible-light-mediated synthetic photochemistry in continuous flow is described. Using an operationally simple photoreactor design, several Ru(bpy)(3)(2+)-catalyzed transformations were performed with 10-50 fold rate enhancement over the corresponding batch methods. In the process, lower catalyst loadings were needed to produce the desired products in excellent yields within residence times between 1 and 30 min, while minimal waste byproducts were formed. The process is readily scalable and provides access to large quantities of product in relatively short time.