1: 95 percent / chromic oxide, pyridine / CH2Cl2; dimethylformamide / 1 h / Ambient temperature 2: 89 percent / sodium chlorite, 2-methyl-2-butene, sat. aq. potassium dihydrogen phosphate, t-BuOH / 5 h / Ambient temperature 3: 56 percent / tetrabutylammonium fluoride / tetrahydrofuran / 0.25 h / 0 °C View Scheme

pyridine; chromium(VI) oxide in dichloromethane; N,N-dimethyl-formamide 1 h; Ambient temperature;

Multi-step reaction with 2 steps 1: 95 percent / chromic oxide, pyridine / CH2Cl2; dimethylformamide / 1 h / Ambient temperature2: 89 percent / sodium chlorite, 2-methyl-2-butene, sat. aq. potassium dihydrogen phosphate, t-BuOH / 5 h / Ambient temperature