1H-imidazole in tetrahydrofuran 12 h; Heating;

1: 83 percent / p-TsOH / dimethylformamide / 15 h / Ambient temperature 2: 1.) CuI / 1.) ether, cyclohexane, -70 deg C, 2.) ether, cyclohexane, 0 deg C, 2 h 3: 1.) L-Selectride, 2.) n-Bu4NF / 1.) THF, -78 deg C. 30 min, 2.) THF, RT, 3 h 4: 26 percent / Ph3P, CBr4 / CH2Cl2 / 15 h / Ambient temperature 5: 8 percent / H2O2, CF3COOAg / diethyl ether / 0.5 h / 0 °C 6: 69 percent / NaBH4 / methanol / 0.08 h / 0 °C View Scheme

toluene-4-sulfonic acid in N,N-dimethyl-formamide 10 h; Ambient temperature;

in N,N-dimethyl-formamide T=50°C; 24 h; Var. cat., TsOH, room temp. 1h;