Abstract
Thio-Claisen rearrangement of symmetrically substituted 1,4-but-2-ynes (3a,b and 4) exhibit tandem cyclization and afforded compounds 5a,b and 6 in good yields. These sulphides 3a,b and 4 were in turn prepared from commercially available thiophene. The key step in this transformation is tandem [3,3] sigmatropic rearrangement.
Keywords: Thio-Claisen rearrangement, mercaptothiophene, regioselectivity, tetracyclic sulphur compounds, tandem cyclisation