trimethylsilyl trifluoromethanesulfonate in 1,2-dichloro-ethane T=0°C; 3 h;

1: 84 percent / Me3SiOTf / 1,2-dichloro-ethane / 3 h / 0 °C 2: p-TsOH*H2O / dimethylformamide / 20 h / 20 °C 3: 61 percent / NaH / dimethylformamide / 20 h / 20 °C View Scheme

1: 84 percent / Me3SiOTf / 1,2-dichloro-ethane / 3 h / 0 °C 2: p-TsOH*H2O / dimethylformamide / 20 h / 20 °C 3: 61 percent / NaH / dimethylformamide / 20 h / 20 °C 4: 77 percent / p-TsOH*H2O / methanol; dioxane / 1) 1 h, 60 deg C, 2) 45 min, 85 deg C View Scheme

1: 76.8 percent / SnCl4 / CH2Cl2 / 15 h 2: BuNH2 / ethanol / Heating 3: 250 mg / pyridine / 25 °C 4: 71 percent / 1M NaOMe / methanol / 25 °C View Scheme

1.1: boron trifluoride diethyl etherate / chloroform / 0.17 h / 0 - 20 °C / Inert atmosphere 1.2: 2 h / 20 °C / Inert atmosphere 2.1: methanol; sodium methylate / 1.5 h / 20 °C / pH 9 3.1: toluene-4-sulfonic acid / N,N-dimethyl-formamide / 20 - 50 °C 4.1: sodium hydride / N,N-dimethyl-formamide; mineral oil / 0.5 h / Inert atmosphere 4.2: 20 °C / Inert atmosphere 5.1: hydrogenchloride; sodium cyanoborohydride / tetrahydrofuran; diethyl ether / 5 h / 0 - 20 °C / Molecular sieve 6.1: N-iodo-succinimide; silver trifluoromethanesulfonate / dichloromethane / 0.17 h / 20 °C / Inert atmosphere View Scheme