1: 1.) BuLi / 1.) THF, hexane, from -30 deg C to -20 deg C, 30 min, 2.) THF, hexane, from -30 deg C to 0 deg C, 4 h 2: 70.1 percent / TsOH / benzene / 0.5 h / Heating 3: 98 percent / CuO, CuCl2 / acetone / 1.5 h / Heating 4: 71 percent / NaOH / methanol / Heating View Scheme

lithium carbonate; lithium bromide in N,N-dimethyl-formamide T=150°C; 3 h;

1: 1.) BuLi / 1.) THF, hexane, from -30 deg C to -20 deg C, 30 min, 2.) THF, hexane, from -30 deg C to 0 deg C, 4 h 2: 70.1 percent / TsOH / benzene / 0.5 h / Heating 3: 98 percent / CuO, CuCl2 / acetone / 1.5 h / Heating View Scheme