The synthesis of thieno [3, 2-b] pyridines was achieved using a three-step process allowing the construction of the thiophenic ring with 17–34% overall yields. The key step was the regioselective lithiation–bromination of the 3-methylthiopyridine induced by BuLi–LiDMAE superbase followed by Sonogashira coupling and halogenocyclization producing the fused heterocycles.
[Verbeek, Jacob; George, Albert V. E.; Jong, Robertus L. P. de; Brandsma, Lambert Journal of the Chemical Society, Chemical Communications, 1984 , # 4 p. 257 - 258]