1: 64 percent / BF3*THF / tetrahydrofuran / 1.) room temp., 15 min, 2.) reflux, 24 h 2: 80 percent / 5percent aq. NaOH / 1 h / Ambient temperature 3: Et3N / CH2Cl2 / 1 h / Ambient temperature 4: DBU / toluene / 1 h / 100 °C 5: 1.) O3, 2.) Me2S / 1.) MeOH, -78 deg C, 2.) -78 deg C to room temp. 6: Jones reagent / acetone / 2 h / 0 °C View Scheme

1: 64 percent / BF3*THF / tetrahydrofuran / 1.) room temp., 15 min, 2.) reflux, 24 h 2: 80 percent / 5percent aq. NaOH / 1 h / Ambient temperature 3: Et3N / CH2Cl2 / 1 h / Ambient temperature 4: DBU / toluene / 1 h / 100 °C 5: 1.) O3, 2.) Me2S / 1.) MeOH, -78 deg C, 2.) -78 deg C to room temp. 6: Jones reagent / acetone / 2 h / 0 °C View Scheme

1: 64 percent / BF3*THF / tetrahydrofuran / 1.) room temp., 15 min, 2.) reflux, 24 h 2: 80 percent / 5percent aq. NaOH / 1 h / Ambient temperature 3: Et3N / CH2Cl2 / 1 h / Ambient temperature 4: DBU / toluene / 1 h / 100 °C 5: 1.) O3, 2.) Me2S / 1.) MeOH, -78 deg C, 2.) -78 deg C to room temp. View Scheme