1.1: 5.1 g / H2SO4 / 20 h / Heating 2.1: LDA / tetrahydrofuran; hexane / 0.5 h / -70 °C 2.2: 73 percent / tetrahydrofuran; hexane / 2 h / -70 °C 3.1: SOCl2; pyridine / 0.17 h / 0 °C 3.2: t-BuOK / o-xylene / 0.08 h / 160 °C 3.3: 7 percent / MgCl2*6H2O / dimethylsulfoxide / 3 h / 160 °C View Scheme