Synthesis of Double‐Thio‐Functionalized Pentasubstituted Pyridines Using α‐Enemalononitrile Ketene Dithioacetals and Thiophenols and Their Selective Arylthio Substitution Reactions

We report an addition/cyclization reaction between α‐enemalononitrile ketene dithioacetal and thiophenols that rapidly generates double‐thio‐functionalized pentasubstituted pyridines. This reaction proceeds under mild conditions without oxidants or transition metals, offering broad substrate scope and excellent functional group tolerance. Additionally, the products can easily undergo selective aromatic thio substitution reactions. The reaction mechanism is likely to involve the formation of an electron‐donor–acceptor (EDA) complex.