p-TSA/Base-Promoted Propargylation/Cyclization of β-Ketothioamides for the Regioselective Synthesis of Highly Substituted (Hydro)thiophenes.
Metal-free, p-toluenesulfonic acid (p-TSA)-mediated, straightforward propargylation of β-ketothioamides with aryl propargyl alcohol has been achieved at room temperature. In addition, the reaction also provided thiazole rings as byproducts. Furthermore, the propargylated thioamides undergo intramolecular 1,5-cyclization to afford fully substituted (hydro)thiophenes in the presence of base. Notably, the approach is pot, atom, and step economical (PASE).
Organic Chemistry Section, Chemical Science and Technology Division, National Institute for Interdisciplinary Science and Technology (CSIR) , Trivandrum 695019, India.
Ganesh Chandra
GC
Nandi
Department of Chemistry, Institute of Science, Banaras Hindu University , Varanasi 221005, India.
Maya Shankar
MS
Singh