boron tribromide T=-78°C;

1: 93 percent / DMAP / CH2Cl2 / 1 h / 0 °C 2: 90 percent / CF3COOH / H2O; tetrahydrofuran / 5 h 3: 83 percent / NaBH(OAc)3 / toluene / 0.75 h / 80 °C 4: 90 percent / pyridine / CH2Cl2 / 18 h / 4 °C 5: 73 percent / Na2S / dimethylformamide / 3 h / 100 °C 6: 82 percent / diethyl azodicarboxylate, PPh3 / tetrahydrofuran / 0.83 h / Ambient temperature 7: 81 percent / K2CO3 / methanol / 0.5 h 8: 94 percent / DMAP / CH2Cl2 / 1 h / 0 °C 9: 26 percent / K2CO3 / dimethylsulfoxide / 85 °C 10: 1) BBr3, 2) aq. NH3 / 1) CH2Cl2, 2) CH2Cl2, 45 min View Scheme

1: 90 percent / pyridine / CH2Cl2 / 18 h / 4 °C 2: 73 percent / Na2S / dimethylformamide / 3 h / 100 °C 3: 82 percent / diethyl azodicarboxylate, PPh3 / tetrahydrofuran / 0.83 h / Ambient temperature 4: 81 percent / K2CO3 / methanol / 0.5 h 5: 94 percent / DMAP / CH2Cl2 / 1 h / 0 °C 6: 26 percent / K2CO3 / dimethylsulfoxide / 85 °C 7: 1) BBr3, 2) aq. NH3 / 1) CH2Cl2, 2) CH2Cl2, 45 min View Scheme

1: 81 percent / K2CO3 / methanol / 0.5 h 2: 94 percent / DMAP / CH2Cl2 / 1 h / 0 °C 3: 26 percent / K2CO3 / dimethylsulfoxide / 85 °C 4: 1) BBr3, 2) aq. NH3 / 1) CH2Cl2, 2) CH2Cl2, 45 min View Scheme

1: 90 percent / CF3COOH / H2O; tetrahydrofuran / 5 h 2: 83 percent / NaBH(OAc)3 / toluene / 0.75 h / 80 °C 3: 90 percent / pyridine / CH2Cl2 / 18 h / 4 °C 4: 73 percent / Na2S / dimethylformamide / 3 h / 100 °C 5: 82 percent / diethyl azodicarboxylate, PPh3 / tetrahydrofuran / 0.83 h / Ambient temperature 6: 81 percent / K2CO3 / methanol / 0.5 h 7: 94 percent / DMAP / CH2Cl2 / 1 h / 0 °C 8: 26 percent / K2CO3 / dimethylsulfoxide / 85 °C 9: 1) BBr3, 2) aq. NH3 / 1) CH2Cl2, 2) CH2Cl2, 45 min View Scheme

1: 73 percent / Na2S / dimethylformamide / 3 h / 100 °C 2: 82 percent / diethyl azodicarboxylate, PPh3 / tetrahydrofuran / 0.83 h / Ambient temperature 3: 81 percent / K2CO3 / methanol / 0.5 h 4: 94 percent / DMAP / CH2Cl2 / 1 h / 0 °C 5: 26 percent / K2CO3 / dimethylsulfoxide / 85 °C 6: 1) BBr3, 2) aq. NH3 / 1) CH2Cl2, 2) CH2Cl2, 45 min View Scheme

1: 94 percent / DMAP / CH2Cl2 / 1 h / 0 °C 2: 26 percent / K2CO3 / dimethylsulfoxide / 85 °C 3: 1) BBr3, 2) aq. NH3 / 1) CH2Cl2, 2) CH2Cl2, 45 min View Scheme

2: n-Bu3SnH, AIBN / toluene / Heating 3: HCl, H2O / methanol 4: NaIO4 / methanol; H2O 5: NaBH4 / methanol 6: NaH, nBu4NI / tetrahydrofuran 7: Dowex 50W-XB(H) 8: DMAP / CH2Cl2 9: TFA / tetrahydrofuran; H2O 10: 83 percent / NaBH(OAc)3 / toluene / Heating 11: 90 percent / pyridine / CH2Cl2 12: 73 percent / Na2S / dimethylformamide 13: 82 percent / Ph3P, DEAD / tetrahydrofuran 14: 89 percent / K2CO3 / methanol 15: DMAP / CH2Cl2 16: 38 percent / K2CO3 / dimethylsulfoxide / Heating 17: BBr3 / -78 °C View Scheme

1: NaH, nBu4NI / tetrahydrofuran 2: Dowex 50W-XB(H) 3: DMAP / CH2Cl2 4: TFA / tetrahydrofuran; H2O 5: 83 percent / NaBH(OAc)3 / toluene / Heating 6: 90 percent / pyridine / CH2Cl2 7: 73 percent / Na2S / dimethylformamide 8: 82 percent / Ph3P, DEAD / tetrahydrofuran 9: 89 percent / K2CO3 / methanol 10: DMAP / CH2Cl2 11: 38 percent / K2CO3 / dimethylsulfoxide / Heating 12: BBr3 / -78 °C View Scheme