1: Ph3P; H2O 2: Et3N 3: 70 percent / 1,2-dichloro-benzene / Heating 4: LiOH 6: 45 percent / TMSOTf / various solvent(s) / -78 - -50 °C 7: 62 percent / TMSOTf; Et3N / CH2Cl2 / 0 - 10 °C 8: HCl View Scheme

1.1: 95 percent / Ph3P / tetrahydrofuran; H2O / 50 h / 20 °C 2.1: 98 percent / DMAP; Et3N / diethyl ether / 7 h / 20 °C 3.1: 60 percent / various solvent(s) / 66 h / Heating 4.1: 99 percent / Et3N; 4-(dimethylamino)pyridine / CH2Cl2 / 10 h / 35 °C 5.1: 99 percent / aq. LiOH / tetrahydrofuran / 12 h 6.1: 45 percent Turnov. / trimethylsilyltriflate / various solvent(s) / -78 - -60 °C 7.1: 62 percent / Et3N; trimethylsilyl triflate / CH2Cl2 / 2 h / 0 °C 8.1: HCl / diethyl ether / 1 h / 20 °C 8.2: 98 percent / 4-(dimethylamino)pyridine; Et3N / diethyl ether / 10 h / 25 °C View Scheme