An Easy Approach to the Synthesis of New Fused 3-Aryl-5- trifluoromethyl-7,8-dihydro-6H-thieno [2,1-f] [1,2] thiazine 1-Oxide System

A new series of 4-alkyl(aryl)-4-tetramethylenesulfoximide-1,1,1-trifluoroalk-3-en-2-ones has been prepared from the O,N-exchange reactions of 4-alkyl(aryl)-4-alkoxy-1,1,1-trifluoroalk-3-en-2-ones with the cyclic S,Stetramethylenesulfoximide in absence of solvent, in good yields. Subsequently, the easy preparation of a new series of a fused heterocyclic system of 3-aryl-5-trifluoromethyl-7,8-dihydro-6H-thieno[2,1-f][1,2]thiazine 1-oxide derivatives (60- 85% yields) from intramolecular cyclization reactions of sulfoximide enones employing potassium t-butoxide in diethyl ether at reflux is also reported.