1: 96 percent / Bu4NF / tetrahydrofuran 2: 1.) BuLi / 1.) THF, -78 deg C 3: toluene / Irradiation 4: 1.) O3, 2.) Me2S / 1.) CH2Cl2, -78 deg C 5: 79 percent / NaH / tetrahydrofuran 6: 1.) HCl, 2.) DBU / 1.) CH2Cl2, MeOH, 2.) toluene, reflux 7: 76 percent / Na(Hg), Na2HPO4 / methanol / 0.17 h / -40 °C View Scheme