Paired Pulsed Decarboxylative Hydroxylation Designed by Online Electrochemistry–Mass Spectrometry

We present a novel strategy for optimizing paired pulsed electrosynthesis by real-time monitoring of redox processes at the electrode interface using voltammetry–electrospray ionization mass spectrometry (VESI-MS). VESI-MS provides molecular insight into interfacial events, enabling the rational design of voltage pulses and synchronization of redox reactions, facilitating the discovery of new alternating current (AC) electrochemical transformations. We apply this approach to develop a selective decarboxylative hydroxylation by coupling oxygen reduction with the oxidative decarboxylation of a carboxylic acid. The pilot study with 2-phenylpropionic acid yields 1-phenylethanol with excellent selectivity using only molecular oxygen, KPF₆, water, and carbon electrodes. This work opens new possibilities for the design of pulsed electrosynthetic reactions.