1: PPh3; HBr / toluene / 6 h 2: 99 percent / DIBAL / CH2Cl2 / -78 °C 3: 96 percent / DABCO / W(CO)6 / tetrahydrofuran / 65 °C / Irradiation 4: Bu4NF / tetrahydrofuran 5: Et3N; DMAP / CH2Cl2 6: 71 percent / PPh3; HBr / toluene / 6 h 7: 98 percent / DIBAL / CH2Cl2 / -78 °C 8: DABCO / W(CO)6 / tetrahydrofuran / 65 °C / Irradiation 9: Et3N; DMAP / CH2Cl2 10: PPh3; HBr / CHCl3 11: (NH4)HF2; N-methylpyrrolidine / dimethylformamide / 70 °C 12: NaOMe / methanol View Scheme