1: 70 percent / DMAP / 0.33 h / 40 °C 2: 70 percent / Amberlyst A-21 / diethyl ether / 2 h / Ambient temperature 3: 55 percent / n-Bu3SnH, AIBN / toluene / 0.5 h / Heating 4: 0.034 g / sodium borohydride / propan-2-ol; tetrahydrofuran / -78 deg C to rt, overnight 5: 80 percent / n-tetrabutylammonium iodide, NaH / tetrahydrofuran / 18 h / Ambient temperature 6: 85 percent / 48percent aq. HF / acetonitrile / 1.5 h / Ambient temperature 7: 1.) oxalyl chloride, DMSO 2.) triethylamine / 1.) CH2Cl2, -60 deg C, 15 min 2.) -60 deg C, 15 min 8: 78 percent / BF3.Et2O, bis(trimethylsilyl)peroxide / CH2Cl2 / 1.5 h / Ambient temperature; 2 9: 42 percent / boron trichloride / CH2Cl2; hexane / 4 h / -78 °C View Scheme