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.