THE FIRST 1,2,4-THIADISILETANE RING COMPOUND - SYNTHESIS FROM AN OVERCROWDED SILYLENE AND CARBON-DISULFIDE

Treatment of an extremely hindered disilene, (Z)-R(mes)Si=Si(mes)R (R = 2,4,6-tris[bis(trimethylsilyl)-methyl]phenyl, mes = mesityl) with ca rbon disulfide in THF at 60 degrees C gives a novel 1,2,4-thiadisileta ne-3-thione derivative, the formation of which is most likely interpre ted in terms of a stepwise 2:1 addition reaction of the thermally gene rated overcrowded silylene R(mes)Si: to CS2 followed by a skeletal rea rrangement of the resulting 3,3'-spirobi[1,2-thiasilirane] intermediat e.