Beschreibung:
<jats:p><jats:bold>1,2,4‐Oxadithietanes and a 1,2,4‐Oxadithiete</jats:bold></jats:p><jats:p>SO<jats:sub>3</jats:sub> adds to (pentafluoro‐λ<jats:sup>6</jats:sup>‐sulfanyl)ethenes <jats:bold>2</jats:bold> with formation of 1,2‐oxathietane <jats:bold>1</jats:bold> and 1,2,4‐oxadithietanes <jats:bold>3</jats:bold>. The latter class of compounds (examples <jats:bold>4a, b</jats:bold>) can also be obtained from SO<jats:sub>3</jats:sub> and alkylidenesulfur tetrafluorides F<jats:sub>3</jats:sub>C‐RC = SF<jats:sub>4</jats:sub>. HOSO<jats:sub>2</jats:sub>F elimination from <jats:bold>3</jats:bold> affords 3‐methylene‐1,2,4‐oxadithietanes <jats:bold>5</jats:bold>. HF elimination from <jats:bold>4a</jats:bold> occurs within the ring, resulting in the first oxadithiete <jats:bold>6</jats:bold>. This isomerizes upon heating to an alkylidenesulfur difluoride oxide FSO<jats:sub>2</jats:sub>(F<jats:sub>3</jats:sub>C)CSF<jats:sub>2</jats:sub>O.</jats:p>