6-O-l-Ascorbyl selenoesters, thioesters and telluroesters can be efficiently and directly prepared from l-ascorbic acid and suitable functionalised chalcogenoesters through lipase-catalysed transesterification reactions.

The synthesis and the evaluation of the thiol peroxidase like antioxidant properties of -functionalized symmetric and non-symmetric organochalcogenides have been explored. The tested catalysts were synthesized exploiting the reactivity of strained heterocycles with silyl chalcogenides. Oxygen-, nitrogen-, and sulfur-containing selenides and tellurides were efficiently achieved from the corresponding epoxides, aziridines, and thiiranes through mild and regioselective ring opening reactions. The thiol peroxidase catalytic activity was investigated by using the dithiothreitol (DTT) oxidation model. The results showed that the nature of the -substituent plays a crucial role in modulating the catalytic properties of the studied GPx mimics. This effect can be reasonably ascribed to the presence of chalcogen bonding interactions involving the selenium or the tellurium atom and the heteroatom (O, S) placed on the moiety at C-2. GRAPHICAL ABSTRACT