Synthesis of Thiacyclic Compounds

The esters of 3-mercaptopropionic acid 1 are used as building blocks for thiacyclic compounds.¹⁾ For example, condensation of 1a with methyl acrylate gives tetrahydrothiopyranone.^1a) This is then used for the formation of thienothiazepinone skelton^1b) and thiopyranopyrrole skelton.^1c) 1 is also utilized as a chain transfer agent in radical polymerizations.²⁾