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