1: 1.75 g / diethyl ether 2: 87 percent / H2 / Pd/C / ethanol / 5 h / 2585.81 Torr 3: Et3N / CH2Cl2 4: Na2S; sulphur / dimethylformamide / 24 h / 90 °C 5: K2CO3 / methanol; H2O View Scheme

With  dipyridinium dichromate in  N,N-dimethyl-formamide  0 deg C, then RT, 24 h;   

Multi-step reaction with 4 steps 1.1: Mg; CH2BrCH2Br / tetrahydrofuran / 1 h / 20 °C1.2: LiCuCl4 / tetrahydrofuran / 1 h / -78 °C1.3: 90 percent / tetrahydrofuran / -78 - 20 °C2.1: 85 percent / TBAI; NaH / dimethylformamide / 2 h / 20 °C3.1: BH3*DMS / tetrahydrofuran / 2 h / 20 °C3.2: 88 percent / aq. NaOEt; H2O2 / tetrahydrofuran / 2 h / 20 °C4.1: aq. NaCl2O; NaOCl; TEMPO / acetonitrile; aq. phosphate buffer / 35 °C / pH 6.7  

Multi-step reaction with 3 steps 1.1: 85 percent / TBAI; NaH / dimethylformamide / 2 h / 20 °C2.1: BH3*DMS / tetrahydrofuran / 2 h / 20 °C2.2: 88 percent / aq. NaOEt; H2O2 / tetrahydrofuran / 2 h / 20 °C3.1: aq. NaCl2O; NaOCl; TEMPO / acetonitrile; aq. phosphate buffer / 35 °C / pH 6.7  

Multi-step reaction with 2 steps 1.1: BH3*DMS / tetrahydrofuran / 2 h / 20 °C1.2: 88 percent / aq. NaOEt; H2O2 / tetrahydrofuran / 2 h / 20 °C2.1: aq. NaCl2O; NaOCl; TEMPO / acetonitrile; aq. phosphate buffer / 35 °C / pH 6.7