An indium-catalyzed reaction of lactones and a disilathiane leading to thiolactones is described. The direct synthesis of thiolactones from lactones with an appropriate sulfur source is one of the most attractive approaches in organic and pharmaceutical chemistry. In this context, we found an indium-catalyzed direct conversion of lactones into thiolactones in the presence of elemental sulfur and a
Boron trifluoride and indium(III) trifluoromethanesulfonate were found to efficiently catalyse the isomerisation of thionolactones to thiolactones in good yields. When applied to an optically active γ-thionolactone, the isomerisation reaction proceeded with a complete inversion of configuration by using BF3·Et2O.
A series of gamma-thionolactones was synthesized, with good yields, using a new combination of Lawesson's reagent (LR) and hexamethyldisiloxane (HMDO) in solvent-free conditions under microwave irradiation. (C) 2003 Elsevier Ltd. All rights reserved.