1: 30percent HBr/HOAc / 12 h / 20 °C 2: 89 percent / 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 1-hydroxybenzotriazole (HOBT), Et3N / tetrahydrofuran 3: TFA / H2O; toluene 4: DDQ 5: diisobutylaluminum hydride (DIBAH) / CH2Cl2 6: 1.) NaBH4; 2.) aq. NaOH / 1.) MeOH 7: 72 percent / 48percent HBr View Scheme

1: 30percent HBr/HOAc / 12 h / 20 °C 2: 89 percent / 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 1-hydroxybenzotriazole (HOBT), Et3N / tetrahydrofuran 3: TFA / H2O; toluene 4: DDQ 5: diisobutylaluminum hydride (DIBAH) / CH2Cl2 6: 1.) NaBH4; 2.) aq. NaOH / 1.) MeOH View Scheme

1: 30percent HBr/HOAc / 12 h / 20 °C 2: 89 percent / 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 1-hydroxybenzotriazole (HOBT), Et3N / tetrahydrofuran 3: TFA / H2O; toluene 4: DDQ 5: diisobutylaluminum hydride (DIBAH) / CH2Cl2 6: 1.) NaBH4; 2.) aq. NaOH / 1.) MeOH 7: 72 percent / 48percent HBr 8: 91 percent / CH2Cl2; propan-1-ol View Scheme