Development of a Continuous-Flow Microreactor for Asymmetric Sulfoxidation Using a Biomimetic Manganese Catalyst.

Asymmetric sulfoxidation catalyzed by a biomimetic manganese complex under continuous-flow microreactor is described. The reaction is conducted in microreactor, it can rapidly (<4 min) oxidize a wide scope of sulfides with high yield (up to 91%) and excellent enantioselectivity (up to 99% ee), and allows shorter reaction times, easier scale-up and lower catalyst loadings than its batchwise counterpart. Additionally, a convenient numbering-up strategy for the scale-up of asymmetric sulfoxidation has been developed which enables a direct scaling of the reaction to 5 g affording the corresponding sulfoxides within 20 min.