Ionic liquids-promoted multi-component reaction: Green approach for highly substituted 2-aminofuran derivatives

The three-component coupling of aldehyde, dimethyl acetylenedicarboxylate (DMAD) and cyclohexyl isocyanide proceeds efficiently in [bmim]BF4 ionic medium under extremely mild conditions to afford the corresponding 2-aminofuran derivatives in high yields. The zwitterionic intermediate formed in situ from DMAD and isocyanide shows enhanced reactivity in ionic liquids, thereby reducing reaction times and improving the yields significantly. Ionic liquid helps to avoid the use of highly toxic and environmentally unfavorable benzene as solvent for this conversion. The recovered ionic liquid was reused for five to six times with consistent activity.