1: 98.4 percent / m-chloroperbenzoic acid / CH2Cl2 / Ambient temperature 2: tert-BuOK / dimethylsulfoxide; tetrahydrofuran / 0.17 h / Ambient temperature 3: Al-Hg / tetrahydrofuran; H2O / 0.67 h / Heating 4: conc. H2SO4 / ethanol / 0.33 h / Heating View Scheme

1: 98.4 percent / m-chloroperbenzoic acid / CH2Cl2 / Ambient temperature 2: tert-BuOK / dimethylsulfoxide; tetrahydrofuran / 0.17 h / Ambient temperature 3: Al-Hg / tetrahydrofuran; H2O / 0.67 h / Heating View Scheme

1: 97.8 percent / LDA / tetrahydrofuran / 1.) 1 h, -78 deg C, 2.) 2 h, ice bath, 3.) 0.5 h, r.t. 2: 100 percent / NaIO4 / H2O; methanol / 20 h / Ambient temperature 3: LDA / tetrahydrofuran / 1.) -78 deg C, 30 min, 2.) 30 min, ice bath 4: Al-Hg / tetrahydrofuran; H2O / 6 h / Heating View Scheme