1: 85 percent / p-toluenesulfonic acid hydrate / 36 h / Heating 2: hydrogen / Lindlar catalyst / hexane; ethyl acetate / 0 °C 3: 96 percent / carbon tetrabromide, triphenylphosphine / CH2Cl2 / 0.67 h 4: 99.9 percent / NaI / acetone / 0.08 h / with longer reaction time the cis-isomer began to isomerized to trans-isomer 5: 1.) n-BuLi; 2.) CuI-Bu3P, and Bu3P / 1.) THF, -78 deg C, 20 min, 30 min; 2.) THF, ether, -78 deg C 10 min, - 30 deg C 1 h; 3.) THF, ether, HMPA, -30 deg C, 3 h 6: 78 percent / pyridine, 50percent aq. HF / 1.) 0 deg C, 30 min; 2.) rt, 4.5 h 7: aluminum amalgam / tetrahydrofuran; H2O / addition in equal portion after 10 h, 17 h and 23h; rt 15 h View Scheme

sodium iodide in acetone 0.0833333 h;

1.1: 6.3 g / BF3 / 4 h / 20 °C 2.1: hydrogen / Lindlar's catalyst / 0 °C 3.1: tetrabromomethane; triphenyl phosphine 4.1: 5.1 g / sodium hydride 5.1: sodium hydride / tetrahydrofuran / 2 h / -5 °C 5.2: 74 percent / tetrahydrofuran; various solvent(s) / -78 - -25 °C View Scheme

potassium carbonate in N,N-dimethyl-formamide 8 h; Ambient temperature;

potassium carbonate in dimethyl sulfoxide 5 h;

in diethyl ether 12 h; Ambient temperature;

1: 85 percent / p-toluenesulfonic acid hydrate / 36 h / Heating 2: hydrogen / Lindlar catalyst / hexane; ethyl acetate / 0 °C 3: 96 percent / carbon tetrabromide, triphenylphosphine / CH2Cl2 / 0.67 h 4: 99.9 percent / NaI / acetone / 0.08 h / with longer reaction time the cis-isomer began to isomerized to trans-isomer View Scheme

sulfuric acid in tetrahydrofuran 72 h; Ambient temperature;

1: 6.3 g / BF3 / 4 h / 20 °C 2: hydrogen / Lindlar's catalyst / 0 °C 3: tetrabromomethane; triphenyl phosphine View Scheme