One-Pot Synthesis of 4,5-Unsubstituted 1,3-Dithioles and 2-Alkylidene-1,3-dithioles from 1,3-Dithiolane S-Oxides - Schaumann, Ernst; Winter-Extra, Susanne; Kummert, Knut; Scheiblich, Stefan (Synthesis, 1990)