selenium(IV) oxide; formic acid in 1,4-dioxane T=80°C; 1.25 h;

1: 92 percent / aq. HCl / tetrahydrofuran / 5 h / 20 °C 2: 40 percent / SeO2/SiO2 / tetrahydrofuran / 2 h / 80 °C View Scheme

1: 96 percent / Et3N / CH2Cl2 / 0.75 h / -78 °C 2: 76 percent / Li2CO3 / dimethylformamide / 5 h / 55 °C 3: 97 percent / (NH4)6Mo7O24; aq. H2O2 / aq. ethanol / 6 h / 20 °C 4: 47 percent / 1,8-diazabicyclo[5.4.0]undec-7-ene / benzene / 5 h / Heating 5: 76 percent / Na2HPO4; Na(Hg) / methanol / 0.42 h / -20 - -10 °C 6: 92 percent / aq. HCl / tetrahydrofuran / 5 h / 20 °C 7: 40 percent / SeO2/SiO2 / tetrahydrofuran / 2 h / 80 °C View Scheme

1: 94 percent / P(OMe)3; O2; t-BuOK / tetrahydrofuran; 2-methyl-propan-2-ol / 0.75 h / -40 °C 2: 73 percent / VO(acac)2; t-BuOOH / benzene; decane / 10 h / 20 °C 3: 72 percent / Et3N / CH2Cl2 / 1 h / -10 - -5 °C 4: NaBH4 / methanol / 5 h / 20 °C 5: 39 mg / PPTS / CH2Cl2 / 0.5 h / Heating 6: 90 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / CH2Cl2 / 18 h / 20 °C 7: 96 percent / Et3N / CH2Cl2 / 0.75 h / -78 °C 8: 76 percent / Li2CO3 / dimethylformamide / 5 h / 55 °C 9: 97 percent / (NH4)6Mo7O24; aq. H2O2 / aq. ethanol / 6 h / 20 °C 10: 47 percent / 1,8-diazabicyclo[5.4.0]undec-7-ene / benzene / 5 h / Heating 11: 76 percent / Na2HPO4; Na(Hg) / methanol / 0.42 h / -20 - -10 °C 12: 92 percent / aq. HCl / tetrahydrofuran / 5 h / 20 °C 13: 40 percent / SeO2/SiO2 / tetrahydrofuran / 2 h / 80 °C View Scheme

1: 76 percent / Li2CO3 / dimethylformamide / 5 h / 55 °C 2: 97 percent / (NH4)6Mo7O24; aq. H2O2 / aq. ethanol / 6 h / 20 °C 3: 47 percent / 1,8-diazabicyclo[5.4.0]undec-7-ene / benzene / 5 h / Heating 4: 76 percent / Na2HPO4; Na(Hg) / methanol / 0.42 h / -20 - -10 °C 5: 92 percent / aq. HCl / tetrahydrofuran / 5 h / 20 °C 6: 40 percent / SeO2/SiO2 / tetrahydrofuran / 2 h / 80 °C View Scheme

1: 49 percent / SeO2; aq. AcOH; t-BuOOH / CH2Cl2; decane / 2 h / 20 °C 2: 74 percent / Dess-Martin periodinane / CH2Cl2 / 1.5 h / -40 - 10 °C 3: 74 percent / aq. RhCl3 / aq. ethanol / 0.58 h / 115 °C 4: 94 percent / P(OMe)3; O2; t-BuOK / tetrahydrofuran; 2-methyl-propan-2-ol / 0.75 h / -40 °C 5: 73 percent / VO(acac)2; t-BuOOH / benzene; decane / 10 h / 20 °C 6: 72 percent / Et3N / CH2Cl2 / 1 h / -10 - -5 °C 7: NaBH4 / methanol / 5 h / 20 °C 8: 39 mg / PPTS / CH2Cl2 / 0.5 h / Heating 9: 90 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / CH2Cl2 / 18 h / 20 °C 10: 96 percent / Et3N / CH2Cl2 / 0.75 h / -78 °C 11: 76 percent / Li2CO3 / dimethylformamide / 5 h / 55 °C 12: 97 percent / (NH4)6Mo7O24; aq. H2O2 / aq. ethanol / 6 h / 20 °C 13: 47 percent / 1,8-diazabicyclo[5.4.0]undec-7-ene / benzene / 5 h / Heating 14: 76 percent / Na2HPO4; Na(Hg) / methanol / 0.42 h / -20 - -10 °C 15: 92 percent / aq. HCl / tetrahydrofuran / 5 h / 20 °C 16: 40 percent / SeO2/SiO2 / tetrahydrofuran / 2 h / 80 °C View Scheme

1.1: PPh3; imidazole; I2 / tetrahydrofuran / 3 h / 0 °C 1.2: 94 percent / t-BuOK / tetrahydrofuran; dimethylsulfoxide / 20 °C 2.1: 49 percent / SeO2; aq. AcOH; t-BuOOH / CH2Cl2; decane / 2 h / 20 °C 3.1: 74 percent / Dess-Martin periodinane / CH2Cl2 / 1.5 h / -40 - 10 °C 4.1: 74 percent / aq. RhCl3 / aq. ethanol / 0.58 h / 115 °C 5.1: 94 percent / P(OMe)3; O2; t-BuOK / tetrahydrofuran; 2-methyl-propan-2-ol / 0.75 h / -40 °C 6.1: 73 percent / VO(acac)2; t-BuOOH / benzene; decane / 10 h / 20 °C 7.1: 72 percent / Et3N / CH2Cl2 / 1 h / -10 - -5 °C 8.1: NaBH4 / methanol / 5 h / 20 °C 9.1: 39 mg / PPTS / CH2Cl2 / 0.5 h / Heating 10.1: 90 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / CH2Cl2 / 18 h / 20 °C 11.1: 96 percent / Et3N / CH2Cl2 / 0.75 h / -78 °C 12.1: 76 percent / Li2CO3 / dimethylformamide / 5 h / 55 °C 13.1: 97 percent / (NH4)6Mo7O24; aq. H2O2 / aq. ethanol / 6 h / 20 °C 14.1: 47 percent / 1,8-diazabicyclo[5.4.0]undec-7-ene / benzene / 5 h / Heating 15.1: 76 percent / Na2HPO4; Na(Hg) / methanol / 0.42 h / -20 - -10 °C 16.1: 92 percent / aq. HCl / tetrahydrofuran / 5 h / 20 °C 17.1: 40 percent / SeO2/SiO2 / tetrahydrofuran / 2 h / 80 °C View Scheme

1: 73 percent / VO(acac)2; t-BuOOH / benzene; decane / 10 h / 20 °C 2: 72 percent / Et3N / CH2Cl2 / 1 h / -10 - -5 °C 3: NaBH4 / methanol / 5 h / 20 °C 4: 39 mg / PPTS / CH2Cl2 / 0.5 h / Heating 5: 90 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / CH2Cl2 / 18 h / 20 °C 6: 96 percent / Et3N / CH2Cl2 / 0.75 h / -78 °C 7: 76 percent / Li2CO3 / dimethylformamide / 5 h / 55 °C 8: 97 percent / (NH4)6Mo7O24; aq. H2O2 / aq. ethanol / 6 h / 20 °C 9: 47 percent / 1,8-diazabicyclo[5.4.0]undec-7-ene / benzene / 5 h / Heating 10: 76 percent / Na2HPO4; Na(Hg) / methanol / 0.42 h / -20 - -10 °C 11: 92 percent / aq. HCl / tetrahydrofuran / 5 h / 20 °C 12: 40 percent / SeO2/SiO2 / tetrahydrofuran / 2 h / 80 °C View Scheme

1: 97 percent / (NH4)6Mo7O24; aq. H2O2 / aq. ethanol / 6 h / 20 °C 2: 47 percent / 1,8-diazabicyclo[5.4.0]undec-7-ene / benzene / 5 h / Heating 3: 76 percent / Na2HPO4; Na(Hg) / methanol / 0.42 h / -20 - -10 °C 4: 92 percent / aq. HCl / tetrahydrofuran / 5 h / 20 °C 5: 40 percent / SeO2/SiO2 / tetrahydrofuran / 2 h / 80 °C View Scheme

1: 74 percent / Dess-Martin periodinane / CH2Cl2 / 1.5 h / -40 - 10 °C 2: 74 percent / aq. RhCl3 / aq. ethanol / 0.58 h / 115 °C 3: 94 percent / P(OMe)3; O2; t-BuOK / tetrahydrofuran; 2-methyl-propan-2-ol / 0.75 h / -40 °C 4: 73 percent / VO(acac)2; t-BuOOH / benzene; decane / 10 h / 20 °C 5: 72 percent / Et3N / CH2Cl2 / 1 h / -10 - -5 °C 6: NaBH4 / methanol / 5 h / 20 °C 7: 39 mg / PPTS / CH2Cl2 / 0.5 h / Heating 8: 90 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / CH2Cl2 / 18 h / 20 °C 9: 96 percent / Et3N / CH2Cl2 / 0.75 h / -78 °C 10: 76 percent / Li2CO3 / dimethylformamide / 5 h / 55 °C 11: 97 percent / (NH4)6Mo7O24; aq. H2O2 / aq. ethanol / 6 h / 20 °C 12: 47 percent / 1,8-diazabicyclo[5.4.0]undec-7-ene / benzene / 5 h / Heating 13: 76 percent / Na2HPO4; Na(Hg) / methanol / 0.42 h / -20 - -10 °C 14: 92 percent / aq. HCl / tetrahydrofuran / 5 h / 20 °C 15: 40 percent / SeO2/SiO2 / tetrahydrofuran / 2 h / 80 °C View Scheme