Liquid/liquid heterogeneous reaction monitoring: Insights into biphasic Suzuki-Miyaura cross-coupling

Monitoring the reaction progress of biphasic reaction mixtures has long presented a significant challenge to modern analytical techniques. While a multitude of widely utilized chemical transformations have been performed under such conditions, in-line separation and analysis of each phase have not been possible, inhibiting detailed kinetic and mechanistic studies of these important processes. Herein, we disclose a novel sampling technology capable of accurately monitoring reaction progress in biphasic mixtures using online high-performance liquid chromatography (HPLC) and multinuclear flow nuclear magnetic reso-nance (NMR) spectroscopy. A biphasic sampling platform was devel-oped to circulate a single phase of a biphasic reaction mixture for anal-ysis using these techniques. The utility of this methodology was demonstrated through analysis of boronic acid distribution and specia-tion under basic conditions as well as for monitoring the reaction prog-ress of a biphasic Suzuki-Miyaura cross-coupling.

Automated summary

Monitoring the reaction progress of biphasic reaction mixtures has been a challenge due to the lack of in-line separation and analysis of each phase. This study presents a novel sampling technology using online HPLC and multinuclear flow NMR spectroscopy to accurately monitor the reaction progress in biphasic mixtures. A biphasic sampling platform was developed to circulate a single phase of the mixture for analysis, and its utility was demonstrated in analyzing boronic acid distribution under basic conditions and monitoring the progress of a biphasic Suzuki-Miyaura cross-coupling reaction.