1: 75 percent / methanesulfonic acid / CH2Cl2 / 0.25 h / 0 °C 2: 25 percent / 2,3-dichloro-5,6-dicyanobenzoquinone / benzene / 4 h / Heating 3: 66 percent / H2 / 10percent Pd/C / ethanol / Ambient temperature 4: 58 percent / NaI, trimethylchlorosilane / 70 °C View Scheme