Catalysis in flow: the practical and selective aerobic oxidation of alcohols to aldehydes and ketones

A safe, practical and selective process for the aerobic oxidation of alcohols to aldehydes and ketones has been developed using an Ru catalyst in a continuous flow reactor. Benzylic and allylic alcohols are oxidised selectively to their corresponding aldehydes and ketones, including substrates containing N- and S-heteroatoms. The rate of turnover is compatible with that previously reported using batch or microchannel reactors under optimised conditions. A preliminary kinetic model is derived that is supported by experimental observations. Last but not least, tandem oxidation–olefination may be achieved without the need to isolate the alcohol intermediate or to switch solvent.