Convenient transformation of thioamides and thioketones to their oxygen analogues with singlet oxygen generated from trans-5-hydroperoxy-3,5-dimethyl-1,2-dioxolan-3-yl ethaneperoxate.

An efficient method for the oxidative transformation of thioamides and thioketones to their oxygen analogues with singlet oxygen is reported. Singlet oxygen was produced in situ from the fragmentation of the trans-5-hydroperoxy-3,5-dimethyl-1,2-dioxolane-3-yl ethaneperoxate in the presence of KOH, and it has been explored as an effective oxidant for oxidative desulfurization of thioamides and thioketones. This protocol provides amides and ketones in excellent yields (80–90%) at room temperature under mild conditions. The thioamides reacted very well with this reagent system. The conjugation of neighboring NH and C=S groups appears to enhance yields for thioamides. Further investigation showed that this reagent system is also an efficient system for deprotection of thionoesters to esters. [ABSTRACT FROM AUTHOR]