Zur Alkylierung von 1,3‐Dithietan‐1,1,3,3‐tetroxid (Disulfen) mit Nonafluorbutansulfonsäureestern

Alkylation of 1,3‐Dithietane 1,1,3,3‐Tetroxide (Disulfene) by Nonafluorobutanesulfonates Silyl and alkyl esters of nonafluorobutanesulfonic aicd are extremely powerful substitution reagents for disulfenes. Starting from trans ‐2,4‐trimethylsilyldisulfene ( 1 ) and methyl nonafluorobutanesulfonate ( 11 ), 2,4‐dimethyl‐2,4‐bis(trimethylsilyl)‐1,3‐dithietane 1,1,3,3‐tetroxide ( 2 ) is prepared. 2 is hydrolyzed to 2,4‐dimethyl‐1,3‐dithietane 1,1,3,3‐tetroxide ( 3 ). Rapid H/D exchange reaction of 3 with D 2 O leads to 4 . Compound 3 is deprotonated by aqueous potassium hydroxide and a potassium salt is obtained, the structure of which is most probably 5a . 2,2,4,4‐Tetramethyl‐1,3‐dithietane 1,1,3,3‐tetroxide ( 7 ) is obtained from 5 and methyl iodide, i.e. the ring system remains intact, whereas hydrolysis furnishes the ring‐opened product 6 . — Three new routes for the synthesis of methyl nonafluorobutanesulfonate ( 11 ) via the silver salt 9 or dimethyl sulfate (96% yield) or nonafluorobutanesulfonic anhydride ( 10 ) are described.