2-Aminothiabutadiene as Useful Building Block in the Synthesis of 2-Aminothiopyrans and 2-Aminothiophenes

We report a reliable and regiocontrolled alternative route to unsubstituted 2-aminothiopyrans and 2-aminothiophenes. These sulfur heterocycles were prepared by reaction of protected aminothiabutadiene 1 with acrylic dienophiles or acceptor-substituted halomethyl compounds. All compounds were fully characterized by IR, HRMS, and 13C and 1H NMR spectroscopy.