Synthesis and some chemical properties of the 6-arylsulfonyl-6-polyfluoroalkanoyl-5,6-dihydro-2H-thiins—new fluorine-containing ketones

1,1-Dihydro-1-tolylsulfonyl polyfluoroalkan-2-ones react with phthalimidosulfenyl chloride to form sulfenylated products on the active methylene group, 1-phthalimidothio-1-tolylsulfonyl polyfluoroalkan-2-ones. Decomposition of the latter leads to formation of 1-thioxo-1-tolylsulfonyl polyfluoroalkan-2-ones. These compounds undergo easily the hetero Diels–Alder reaction with electron-rich 1,3-dienes as dienophiles to give polyfluoroalkanoyl substituted derivatives of 5,6-dihydro-2H-thiins. 6-Arylsulfonyl-6-polyfluoroalkanoyl-5,6-dihydro-2H-thiins obtained react with alkali to give 5,6-dihydro-6-p-tolylsulfonyl-2H-thiins and with methanol to give 2-polyfluoroalkanoyl-6H-thiins.