1: 90 percent / triethylamine / benzene / 40 h / Heating 2: 90 percent / glacial acetic acid, DDQ / diethyl ether / 1.) 0 deg C, 1 h, 2.) 25 deg C, 2 h 3: 10 percent 4: 100 percent / aq. HI (57 percent) / benzene / 2 h 5: 68 percent / Me3SiCl, Zn / tetrahydrofuran / Heating 6: 90 percent / sodium hydride / tetrahydrofuran / 4 h / Ambient temperature 7: 100 percent / toluene-4-sulphonic acid / benzene / 0.03 h / Heating View Scheme

1: 78 percent / triethylamine / benzene / 30 h / Heating 2: 78.7 percent / 2,3-dichloro-5,6-dicyanobenzoquinone, acetic acid / benzene / 1.) 1 h, ice-bath, 2.) 3 h, room temperature 3: Zn View Scheme