A mild and cost-effective decarboxylation cyclization method was developed for the synthesis of chiral 5-substituted thiazolidine-2-thione derivatives from β-amino oxazolidinones. This reaction was mediated by CS2 and allowed a highly stereoselective synthesis of linezolid thiazolidine-2-thione derivatives. The chirality of the linezolid base was completely retained in the final product.