Convenient procedure for converting 1,3-dithiolane-2-thiones into 1,3-dithiolan-2-ones

Abstract

1,3-Dithiolan-2-ones have been obtained by reaction of 1,3-dithiolane-2-thiones and epoxides in the presence of HBF₄·Et₂O. The reactions, carried out in anhydrous CH₂CL₂ at 0–5 °C→room temperature (Procedure A) or in anhydrous chlorobenzene at 0–5-→80 °C (Procedure B), gave product yields of 63–95%. By Procedure B it was also possible to isolate the intermediates 1-oxa-4,6,9-trithiaspiro[4.4]nonanes in good yields (66–85%). Reaction pathways are proposed.