Access to Thienopyridine and Thienoquinoline Derivatives via Site-Selective C–H Bond Functionalization and Annulation

To develop of an effective synthetic methodology for biologically relevant thienopyridines, a concise and efficient protocol is described for the synthesis of a series of substituted thienopyridine and thienoquinoline derivatives with high selectivity using EtOCS2K as the sulfur source. The reaction proceeds via metal-free, site-selective C–H bond thiolation and cyclization of the alkynylpyridine and alkynylquinoline substrates.