an extremely facile and efficient procedure which has been developed for the synthesis of dihydropyrrol-2-ones. one-pot four-component reaction of amines, dialkyl acetylenedicarboxylates and formaldehyde in the presence of n,n,n,n-tetramethylguanidinium acetate [tmg][ac] in methanol at ambient temperature provides substituted dihydropyrrol-2-ones in good to high yields. the important aspects of...