1: DIBAL-H / toluene; tetrahydrofuran / 0 °C 2: BuLi / tetrahydrofuran / 0 - 20 °C 3: 40percent aq. HF / Ambient temperature 4: 85 percent / (COCl)2, DMSO / CH2Cl2 / 0.25 h / -70 °C 5: 67 percent / (i-PrO)3P / (dba)3Pd2*CHCl3 / tetrahydrofuran / 2 h / Ambient temperature View Scheme

1: DIBAL-H / toluene; tetrahydrofuran / 0 °C 2: BuLi / tetrahydrofuran / 0 - 20 °C 3: 40percent aq. HF / Ambient temperature 4: 60 percent / (i-PrO)3P / (dba)3Pd2*CHCl3 / tetrahydrofuran / 16 h / Ambient temperature View Scheme