1.1: singlet oxygen; TPFPP / CDCl3 / 24 h / 0 °C / Photolysis 1.2: 83 percent / PPh3 / CDCl3 / 0 °C 2.1: diethyl ether / 3 h / 0 °C View Scheme

1: 1.) CuCl / 1.) Et2O/THF, 15 min, 2.) THF, -80 deg C, 1 h; -40 deg C, 16 h 2: 72 percent / 1.) 30 percent aq. H2O2, LiOH*H2O, H2O, 2.) HCl / tetrahydrofuran / 1.) 0 deg C, 2 h, 2.) RT, 16 h View Scheme

Multi-step reaction with 5 steps 1: 63 percent / H2 / Lindlar catalyst / benzene / 760 Torr2: OsO4, N-morpholine N-oxide monohydrate / dimethylformamide; 2-methyl-propan-2-ol / 4.5 h / -20 °C3: TsOH / acetone / 2 h / Ambient temperature4: 82 percent / LiAlH4 / tetrahydrofuran / 1 h / Ambient temperature5: 82 percent / NaH / paraffin; toluene / 0.5 h / Ambient temperature  

Multi-step reaction with 4 steps 1: OsO4, N-morpholine N-oxide monohydrate / dimethylformamide; 2-methyl-propan-2-ol / 4.5 h / -20 °C2: TsOH / acetone / 2 h / Ambient temperature3: 98 percent / LiOH / tetrahydrofuran; H2O / 7 h / Ambient temperature4: 82 percent / NaH / paraffin; toluene / 0.5 h / Ambient temperature