1: N-iodo-succinimide / trimethylsilyl trifluoromethanesulfonate / tetrahydrofuran / 1.17 h / -78.2 - 0 °C / Molecular sieve 2: triethylamine; triethylamine tris(hydrogen fluoride) / tetrahydrofuran / 0.83 h / 20 °C 3: pyridine / 15 h / 20 °C 4: tetrabutyl ammonium fluoride / tetrahydrofuran / 0.02 h / 20 °C View Scheme