Potential Degradation of 4-Methyltetrahydropyran (4-MeTHP) under Oxidation Conditions

Abstract 4-Methyltetrahydropyran (4-MeTHP) is a next-generation recyclable ether solvent that can be applied to a wide variety of synthetic reaction methods. Previous studies indicated that 4-MeTHP could degrade to some extent with certain oxidants, while the oxidation reactions themselves proceeded in good yields. Here we disclose the potential oxidative degradation pathways of 4-MeTHP when exposed to selected organic-based and metal-based oxidants. Crude NMR analyses revealed that degradation of 4-MeTHP was initiated by C2?H abstraction, giving rise to C2- or C4-oxidized products or the C?C bond cleavage product depending on the oxidants used. This study therefore illustrates possible degradation products of 4-MeTHP under oxidative conditions, which is particularly helpful in predicting and analyzing trace impurities when adopting 4-MeTHP or other ethereal solvents in industrial processes. [Open Access]