1.1: sodium tetrahydroborate / methanol / 0.17 h / 0 - 20 °C / Inert atmosphere 2.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 2 h / 20 °C 3.1: 1-hydroxy-3H-benz[d][1,2]iodoxole-1,3-dione / dimethyl sulfoxide / 30 h / 20 °C 4.1: 2,6-dimethylpyridine; trifluoromethylsulfonic anhydride / dichloromethane / 0.5 h / -78 - -40 °C 4.2: 14 h / -40 - 0 °C View Scheme

1.1: sodium tetrahydroborate / methanol / 0.17 h / 0 - 20 °C / Inert atmosphere 2.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 2 h / 20 °C 3.1: 1-hydroxy-3H-benz[d][1,2]iodoxole-1,3-dione / dimethyl sulfoxide / 30 h / 20 °C 4.1: 2,6-dimethylpyridine; trifluoromethylsulfonic anhydride / dichloromethane / 0.5 h / -78 - -40 °C 4.2: 14 h / -40 - 0 °C View Scheme

tetrabutyl ammonium fluoride in methanol T=20°C; 2 h;

1: sodium tetrahydroborate / methanol / 0.17 h / 0 - 20 °C / Inert atmosphere 2: tetrabutyl ammonium fluoride / tetrahydrofuran / 2 h / 20 °C 3: 1-hydroxy-3H-benz[d][1,2]iodoxole-1,3-dione / dimethyl sulfoxide / 30 h / 20 °C View Scheme