Pyrrothines like thiolutine and other bicyclic 1,2-dithioles of type 1 when unsubstituted in 3-position are marked by their CH acidity. In the presence of weak bases such as triethylamine the pyrrothine 4 degraded via its anion to a thioketene trapped as the 1,3-dithietane 5. The carbenoid anions of