Abstract:

Among the different possible methods leading to nitrogen-containing heterocycles, iminium ion cyclization is a widely used process. Cyclic iminium ions of general structure 1 (Figure 1), bearing a nucleophilic tether with a suitable located oxygen, sulfur or nitrogen, are important building blocks for the preparation of synthetically and biologically relevant condensed heterocycles. The present work describes our findings in the synthesis of enantioenriched new fused thiazolidinyloxazolidines (2) and bisthiazolidines (3) via the generation of cyclic iminium ions (Figure 1).