1: aq. barium hydroxide solution 2: concentrated hydrochloric acid / 140 - 150 °C View Scheme

barium dihydroxide

1: SO2Cl / 1 h / 40 °C 2: NEt3 / CH2Cl2 / 21 h / Ambient temperature 3: LDA / tetrahydrofuran / -78 °C 4: 3N HCl / tetrahydrofuran / 23 h / Ambient temperature 5: NEt3 / 15 h / Ambient temperature 6: 1.) sodium trimethoxyborohydride / 1.) DMF, 65 deg C, 1 h, 2.) DMF, 110 deg C, 1 h 8: 1.) O3, 2.) 1-hexene / 1.) CH2Cl2, -78 deg C, 2.) CCl4, reflux, 30 min 9: 84 percent / 6N HCl / 4.5 h / 150 °C View Scheme