N‐Hydroxyphthalimide Catalyzed Aerobic Oxidation of Aldehydes under Continuous Flow Conditions

Abstract The efficacy of synthetic methodologies is based not only on potent chemistries but also on processing strategies that amplify reaction performance and overall safety. The N ‐hydroxyphtalimide‐catalyzed aerobic oxidation of aldehydes is an environmentally reliable and inexpensive approach for the synthesis of valuable carboxylic acids. However, the reaction may lead to the accumulation of significant amounts of peracid in crude product mixtures thereby generating a considerable safety hazard. Also, in the case of deactivated substrates, long reaction times, high catalyst loading, and stoichiometric additives are required to promote oxidation. Therefore, we developed a flow chemistry‐based process for N ‐hydroxyphtalimide‐catalyzed aldehyde oxidations and exploited its benefits to minimize peracid buildup, thereby enhancing the process safety. By performing the aerobic oxidation of aldehydes under continuous flow conditions, chemically intensified and scalable carboxylic acid formation was obtained even in the reactions of deactivated substrates. Our findings are presented herein. magnified image