Dowex 50 (H(1+)) in water T=70°C; 2 h;

1: 81 percent / Dowex 50 (H(1+)) / H2O / 2 h / 70 °C 2: 23.2 g / pyridine / CHCl3 / 24 h / Ambient temperature 3: hydrogen bromide, acetic acid / CH2Cl2 / 0.17 h 4: 3.28 g / 1,8-diazabicyclo<5.4.0>undec-7-ene / CH2Cl2 / 1.5 h / Ambient temperature 5: 96 percent / molecular sieves 4A, ethanol, N-bromosuccinimide / CH2Cl2 / 0.5 h 6: 1.) silver carbonate, molecular sieves 4A, 2.) sodium borohydride / 1.) CH2Cl2, 15 min, 2.) dioxane, water, 20 min 7: 89 percent / pyridine / 1 h 8: 96 percent / NaOMe / methanol; CH2Cl2 / 4.5 h 9: 1.) molecular sieves 4A, 2.) mercury(II) bromide / 1.) CH2Cl2, 15 min, 2.) CH2Cl2, room temperature, 24 h 10: 53 percent / pyridine / 8 h / Ambient temperature 11: 86 percent / hydrogen, acetic acid / palladium-carbon / ethanol / 2 h / Ambient temperature 12: 1.) molecular sieves 4A, 2.) trimethylsilyl triflate / 1.) CH2Cl2, room temperature, 30 min, 2.) CH2Cl2, room temperature, 45 min 13: 84 percent / sodium methoxide / methanol / 48 h / Heating View Scheme

periodic acid in ethyl acetate 2 h;