1: 85 percent / triethylamine / CH2Cl2 / 0.5 h / Ambient temperature 2: 90 percent / LAH / tetrahydrofuran / 0.67 h / 0 °C 3: 1.) oxalyl chloride, dimethylsulfoxide 2.) triethylamine / 1.) CH2Cl2, -10 deg C, 20 min 2.) -10 deg C, 5 min 4: 53 percent / K2CO3 / methanol / 19 h / 100 °C 5: 73 percent / sodium methoxide / methanol / 2 h / Ambient temperature 6: 85 percent / methanesulfonyl chloride, triethylamine / CH2Cl2 / 1 h / 0 °C 7: 90 percent / NaBH4 / propan-2-ol; CHCl3 / 0.67 h / Ambient temperature 8: 93 percent / aq.HF / acetonitrile / 24 h / Ambient temperature 9: 70 percent / DMAP / 0.33 h / 40 °C 10: 70 percent / Amberlyst A-21 / diethyl ether / 2 h / Ambient temperature 11: 55 percent / n-Bu3SnH, AIBN / toluene / 0.5 h / Heating 12: 0.034 g / sodium borohydride / propan-2-ol; tetrahydrofuran / -78 deg C to rt, overnight 13: 80 percent / n-tetrabutylammonium iodide, NaH / tetrahydrofuran / 18 h / Ambient temperature 14: 85 percent / 48percent aq. HF / acetonitrile / 1.5 h / Ambient temperature 15: 1.) oxalyl chloride, DMSO 2.) triethylamine / 1.) CH2Cl2, -60 deg C, 15 min 2.) -60 deg C, 15 min 16: 78 percent / BF3.Et2O, bis(trimethylsilyl)peroxide / CH2Cl2 / 1.5 h / Ambient temperature; 2 17: 42 percent / boron trichloride / CH2Cl2; hexane / 4 h / -78 °C View Scheme