(i) PBr3, CuBr, Et2O, (ii) Zn; Multistep reaction;

1: pyridine / 1.5 h / Ambient temperature 2: sodium bicarbonate / methanol 3: DIBAL / tetrahydrofuran / 2 h / ice bath 4: 73 percent / tBuOOH, VO(acac)2 / benzene / under standard Sharpless conditions 5: CrO3-pyridine / CH2Cl2 / Ambient temperature 6: silica gel / eluted the column with hexane-ether View Scheme

1: pyridine / 1.5 h / Ambient temperature 2: sodium bicarbonate / methanol 3: DIBAL / tetrahydrofuran / 2 h / ice bath View Scheme