Synthesis of 6,7,9,10-tetrahydro-4H-thieno[3,2-f][1,4]oxathionine and 4,7,8,10-tetrahydro-5H-thieno[2,3-f][1,4]oxathionine by S-ylide rearrangement

Abstract

6,7,9,10-Tetrahydro-4H-thieno[3,2-f][1,4]oxathionine 7 and 4,7,8,10-tetrahydro-5H-thieno[2,3-f][1,4]oxathionine 17 have been synthesized by a [2,3] sigmatropic rearrangement of S-methylides 6 and 16 which are generated by the fluoride ion-induced desilylation of 3-(2-thienyl)-4-[(trimethylsilyl)methyl]-1,4-oxathianium triflate 4 and the 3-(3-thienyl)- analogue 14.