1: 1) SeO2, t-BuOOH, 2) NaBH4 / 1) CH2Cl2, 0 deg C, 8 h, 2) MeOH 2: 1) MsCl, Et3N, 2) LiBr / 1) CH2Cl2, -40 to -20 deg C, 1 h, 2) THF, -20 to 25 deg C, 2 h 3: 85 percent / NaH, n-BuLi / tetrahydrofuran / 1 h / 0 °C 4: 55 percent / Mn(OAc)3*2H2O / acetic acid / 1 h / 70 °C View Scheme