Metal-Free Green Synthesis of 4,5-Diaryl-1,3-dioxolane-2-thiones Scaffolds Via NHC Catalysis

A metal-free, efficient method for the simple and convenient synthesis of aryl group-substituted thiocarbonates under ambient conditions has been developed. The described strategy enabled the practical approach to access diaryl-substituted cyclic thiocarbonates from hydrobenzoin using di(1H-imidazol-1-yl)methanethione (Im2CS) in toluene at reflux. N-Heterocyclic carbene (NHCs) have been used as organocatalysts to convert functionalized aromatic aldehydes to substituted benzoin, which is then rapidly reduced with commercially available sodium borohydride (NaBH4) in one-pot conditions, producing functionalized hydrobenzoin derivatives in good yields. The present method offers a greener approach featuring readily accessible catalysts and reagents, broad substrate scope, operational simplicity, high yields, shorter reaction times, and mild conditions.