Direct 1,5-cycloaddition of sulphur dioxide to cyclo-octatetraene. 9-Thiabarbaralane 9,9-dioxide

Abstract

Reaction of cyclo-octatetraene with antimony pentafluoride in liquid sulphur dioxide leads directly to 9-thiatricyclo[3,3,1,02,8]nona-3,6-diene 9,9-dioxide by unprecedented 1,5 cycloaddition; 9-thiabicyclo[4,2,1]nona-2,4,7-triene 9,9-dioxide is formed concomitantly and is the thermodynamically more stable C8H8O2S isomer.