Recent Advances in the Synthesis of Sulfonylureas

Sulfonylureas are employed in a variety of applications including use as drugs to treat type II diabetes and as plant growth regulators or herbicides. Traditionally, the synthesis of sulfonylureas has been accomplished either by the treatment of sulfamides with isocyanates in the presence of a base or through sulfonamides conversion into N-sulfonyl isocyanates or N-sulfonyl carbamate derivatives which provide the corresponding sulfonylureas upon treatment with amines. Both approaches are severely limited by the weak nucleophilicity of sulfamides and by the difficulty in synthesizing and handling isocyanate species. Such a drawback could be mitigated by the emergence of protocols establishing the labile electrophilic functional groups in situ so that their coupling with nucleophilic partners takes place in one-pot. Recently, the development of environmentally friendly methods to prepare sulfonylurea containing compounds without using harmful reagents has attracted considerable attention. The aim of the minireview is to explore the different protocols emerged in the literature to generate sulfonylureas giving importance to the reaction mechanisms of crucial synthetic steps.