1: 1.) n-BuLi, 1/2CuBr-Me2S 2: DBU / CH2Cl2 / 1 h / -78 °C 3: 60 percent / xylene / 4 h / 140 °C 4: 81 percent / O3, Me2S / 12 h 5: Jones reagent / 0.33 h 6: KOH / 50 °C View Scheme