Mild Deprotection of Dithioacetals by TMSCl / NaI Association in CH3CN

We showed for the first time, the fundamental role of CH₃CN associated to TMSCl/NaI combination to deprotect S,S-ethylene- and S,S-propylene-ketals into ketones. Indeed, if the TMSCl/NaI association leads to the reduction of dithioketals in CH₂Cl₂, we have demonstrated that this association can be used to deprotect a large variety of various dithioketals into ketones in CH₃CN. Otherwise, under mild experimental conditions, O,O-acetals as well as O,S-oxathianes were cleanly deprotected with high yields. It is also possible to easily regenerate the carbonyl function of various hydrazones and imines using this novel protocol. We believe that this metal-free process is a good alternative to other known methodologies used to deprotect dithioketals into ketones.