hydrogenchloride 1a) THF, 0 deg C, 45 min, 1b) 25 deg C, 20 h, 1c) two portions of the diene were added after 20 h and 40 h, respectively 2) THF, 25 deg C, 1 h; Yield given. Multistep reaction;

1: potassium carbonate / N,N-dimethyl-formamide / 4 h / 20 °C 2: hydrogenchloride; water / 1 h / 20 °C 3: N-bromosuccinmide; 2,2'-azo-bisisobutyronitrile / tetrachloromethane; chloroform / 4 h / Reflux 4: zinc / 0.17 h / 20 °C 5: water / N,N-dimethyl-formamide / 16 h / 180 °C View Scheme