1: trimethylsilyl trifluoromethanesulfonate / CDCl3 / 1 h / 20 °C 2: 77 percent / diisobutylaluminium hydride View Scheme

2: trimethylsilyl trifluoromethanesulfonate / CDCl3 / 1 h / 20 °C 3: 77 percent / diisobutylaluminium hydride View Scheme

2: 1. H2 2. triethylamine / Pd/C / 1.in ethanol, 25 grad C, 1 atm, 10 h 2. in methylene chloride, 25 grad C, 1 h 3: 97 percent / CrO3-Py2 4: 70 percent / potassium carbonate / propan-2-ol / 1 h / 50 °C 5: 90 percent / 0.17 h / -20 °C View Scheme