Synthesis of indolizines from pyridinium 1,4-zwitterionic thiolates and propiolic acid derivatives <i>via</i> a formal [4 + 1] pathway
Bin Cheng, Hui Li, Shengguo Duan, Xinping Zhang, Yixuan He, Yuntong Li, Yun Li, Taimin Wang, Hongbin Zhai
Abstract
A novel cyclization reaction of pyridinium 1,4-zwitterionic thiolates and propiolic acid derivatives mediated by triethylamine is described, which allows the facile synthesis of indolizines under mild reaction conditions. The net transformation involves an acetylide-driven formal [5 + 1] annulation reaction followed by a spontaneous ring-contraction/sulfur extrusion process of transient pyridothiazine intermediates.
Topics & Concepts
ChemistryPyridiniumAnnulationTriethylamineAcetylideCombinatorial chemistryOrganic chemistryMedicinal chemistryCatalysisSynthesis and Reactivity of HeterocyclesCyclopropane Reaction MechanismsSynthesis and Characterization of Pyrroles