1: 61 percent / 1.) Ph-S-Et, NCS; 2.) Et3N / 1.) 0 deg C, 2 h, CH2Cl2; 2.) toluene 2: 81 percent / H2O2 / dioxane / 1 h / Ambient temperature 3: 73.79 percent / Dowex 50WX8 H(1+) / ethanol / Heating 4: 1.) RuO2, NaOCl; 2.)(CH3)2CHOH / 1.) 2 h, CHCl3; 2.) r.t. 10 min 5: 81.09 percent / HCl / ethanol / 4 h / Heating View Scheme