1: 65 percent / BF3*OEt2 / tetrahydrofuran / 2 h / -78 - 0 °C 2: 1.) pyridinium toluene-p-sulfonate, 2.) CrO3, acid 4: 1.) n-Bu3SnH, AIBN 5: 61 percent / HF / tetrahydrofuran View Scheme

1: 95 percent / tetrahydrofuran / 12 h / Ambient temperature 3: 1.) CuCN 4: pyridinium p-toluenesulfonate (PPTS) / methanol; diethyl ether 5: CrO3, H+ 6: aq. HF / acetonitrile View Scheme

1: 65 percent / BF3*OEt2 / tetrahydrofuran / 2 h / -78 - 0 °C 2: 1.) pyridinium toluene-p-sulfonate, 2.) CrO3, acid 4: 1.) n-Bu3SnH, AIBN 5: 61 percent / HF / tetrahydrofuran View Scheme

in tetrahydrofuran 12 h; Ambient temperature;

1: 89 percent / NaBr, BF3*Et2O / acetone / 0.5 h / Ambient temperature 2: 1.) (c-C6H11)2BH, 2.) aq. NaOH / 2.) Pd(PPh3)4 / 1.) THF, r.t., 1 h, 2.) benzene, 65 deg C, 1 h 3: 70percent m-CPBA / CH2Cl2 / 1 h / Ambient temperature 4: BF3*Et2O, MeOH / 0.5 h / 0 °C 5: 1.) t-BuLi, 2-thienyl(cyano)copper lithium / 1.) pentane, Et2O, -78 deg C, 30 min; THF, -78 deg C, 30 min, 2.) -78 deg C, 1 h 6: 93 percent / HF*pyridine, pyridine / acetonitrile / 4 h / Ambient temperature View Scheme