A novel arylation of sulfonamides with boronic acids to afford numerous diaryl sulfones via a visible light-mediated N–S bond cleavage other than the typical transition-metal-catalyzed C(O)–N bond activation is described. This methodology, which represents the first catalyst-free protocol for the sulfonylation of boronic acids, is characterized by its simple reaction conditions, good functional group
A novel and efficient solvent-free and heterogeneous method for the synthesis of primary, secondary and bis-N-acylsulfonamides using metal hydrogen sulfate catalysts
Some metal hydrogen sulfates were used as acid catalysts in the N-acylation of different sulfonamides using carboxylic acid chlorides and anhydrides as acylating agents under both heterogeneous and solvent-free conditions. Al(HSO4)(3) and Zr(HSO4)(4) were found to have the highest activity and catalyze the reactions efficiently to furnish the primary N-acyl sulfonamides (RCONHSO2R'), secondary N-acylsulfonamides (RCONR '' SO2R') and bis-N-acylsulfonamnides [RCO(SO2R')N-R ''-N(SO2R')COR] in good to high yield. The mild reaction conditions, inexpensive and low toxicity of catalysts and easy work-up procedure make this method attractive. (C) 2009 Elsevier Ltd. All rights reserved.