1: 30percent HBr / 1) 0 deg C, 15 min, 2) rt, 4 h 2: 30percent HBr, AcOH / ethanol / 4 h / Heating View Scheme

1: 79 percent / OsO4, N-methylmorpholine N-oxide / H2O; acetone; 2-methyl-propan-2-ol / Ambient temperature 2: 30percent HBr / 1) 0 deg C, 15 min, 2) rt, 4 h 3: 30percent HBr, AcOH / ethanol / 4 h / Heating View Scheme