Tris-(8-trimethylsilyl-2,2,6,6-tetramethylbenzo[1,2-d:5,4-d']-bis(1,3)oxathiol-4-yl)methanol (0.62 g, 0.62 mmol) was dissolved in acetonitrile (150 mL). Sodium iodide (0.75 g, 6.0 mmol) and chlorotrimethylsilane (0.65 g, 6.0 mmol) was added in one portion. The mixture was stirred for 20 min and then poured onto diethyl ether/aq. NaHCO3. The aqueous layer was extracted with ether and the combined organic layers were washed twice with water, dried (Na2SO4), evaporated, chromatographed (silica gel; dichloromethane) and finally triturated with ethyl acetate to yield the product as slightly brown crystals.
