An Unexpected Sequence: From Phosphole Sulfide to Phosphole- and Thiophene-Annulated 1,2-Dithiole-3-thiones

The deprotonation of 1-phenyl-3,4-dimethylphosphole sulfide by a bulky base, followed by the reaction of S2Cl2, unexpectedly yields a phosphole-annulated 1,2-dithiole-3-thione. The complexation of this product by [W(CO)5] takes place at CS as expected on the basis of theoretical calculations. Another product results from the unprecedented replacement of the P(S)Ph unit by sulfur, giving the corresponding thiophene derivative.