A facile and direct synthetic entry to tetraalkyl 2,3,4,5-thiophenetetracarboxylate
derivatives is described. This involves the reaction of dialkyl
acetylenedicarboxylates with elemental sulfur in the presence of
triethyl phosphite or an N-heteroaromatic compound such as isoquinoline,
1-methyl-1H-imidazole, or pyridine as
catalyst.
dialkyl acetylenedicarboxylate - elemental sulfur - catalytic reaction - tetraalkyl
2,3,4,5-thiophenetetracarboxylate