titanium tetrachloride in dichloromethane T=0°C; 0.25 h; Yield given;

1: 79 percent / first generation Grubbs' catalyst / CH2Cl2 / 24 h / Heating 2: 85 percent / n-BuLi / tetrahydrofuran / -78 °C 3: PPTS / CH2Cl2 4: TBAF / tetrahydrofuran 5: Et3N; DMAP / CH2Cl2 / 0 °C 6: AgNO3 / acetonitrile 7: NaOAc / dimethylsulfoxide 8: iPr2NEt; LiCl / acetonitrile 9: PPTS / methanol 10: NaBH4 / methanol / -78 °C View Scheme

1.1: NEt3; PivCl / tetrahydrofuran / 1 h / 0 °C 1.2: 94.5 percent / LiCl / tetrahydrofuran / 0 - 20 °C 2.1: TMEDA / CH2Cl2 / 2 h / 0 °C 2.2: 78.7 percent / CH2Cl2 / 0 °C 3.1: 96.7 percent / 2,6-lutidine / dimethylformamide / 24 h / 20 °C 4.1: 95.9 percent / LiBH4 / diethyl ether; methanol; tetrahydrofuran / 0 °C 5.1: 95.8 percent / i-Pr2NEt; Py*SO2 / CH2Cl2; dimethylsulfoxide / 0.25 h / 0 °C 6.1: 97.8 percent / TsOH / methanol / 1 h / 20 °C 7.1: 97.1 percent / PPTS / benzene / Heating 8.1: 89.4 percent / NaHCO3; I2 / acetone; H2O / 0.25 h / 0 °C 9.1: LDA / tetrahydrofuran; hexane / 1 h / -78 °C 9.2: tetrahydrofuran; hexane / -78 - 20 °C 10.1: 2.25 g / TiCl4 / CH2Cl2 / 1 h / -78 °C 11.1: 97 percent / DBU / methanol / 1 h / 0 °C 12.1: BuLi / tetrahydrofuran; hexane / 1 h / -78 °C 12.2: MeCuCNLi / tetrahydrofuran; hexane; diethyl ether / 1 h / -78 °C 12.3: 92.6 percent / tetrahydrofuran; hexane; diethyl ether / 1 h / -78 °C 13.1: 131 mg / (S)-2-methyl-CBS-oxazaborolidine; BH3*Me2S / tetrahydrofuran; toluene / 0.25 h / 0 °C 14.1: 96.4 percent / diethyl ether / 1 h / 0 °C 15.1: 72 percent / Li-naphthalene / tetrahydrofuran / -25 °C 16.1: MnO2 / CH2Cl2 / 3 h / Heating 17.1: 33.6 mg / NaH2PO4; 2-methyl-2-butene; NaClO2 / 2-methyl-propan-2-ol; H2O / 20 °C 18.1: NEt3; 2,4,6-trichlorobenzoyl chloride / tetrahydrofuran / 6 h 18.2: 81 percent / DMAP / tetrahydrofuran; toluene / Heating 19.1: 91 percent / aq. HCl / tetrahydrofuran; H2O / 48 h / 20 °C View Scheme

1.1: 97.8 percent / TsOH / methanol / 1 h / 20 °C 2.1: 97.1 percent / PPTS / benzene / Heating 3.1: 89.4 percent / NaHCO3; I2 / acetone; H2O / 0.25 h / 0 °C 4.1: LDA / tetrahydrofuran; hexane / 1 h / -78 °C 4.2: tetrahydrofuran; hexane / -78 - 20 °C 5.1: 2.25 g / TiCl4 / CH2Cl2 / 1 h / -78 °C 6.1: 97 percent / DBU / methanol / 1 h / 0 °C 7.1: BuLi / tetrahydrofuran; hexane / 1 h / -78 °C 7.2: MeCuCNLi / tetrahydrofuran; hexane; diethyl ether / 1 h / -78 °C 7.3: 92.6 percent / tetrahydrofuran; hexane; diethyl ether / 1 h / -78 °C 8.1: 131 mg / (S)-2-methyl-CBS-oxazaborolidine; BH3*Me2S / tetrahydrofuran; toluene / 0.25 h / 0 °C 9.1: 96.4 percent / diethyl ether / 1 h / 0 °C 10.1: 72 percent / Li-naphthalene / tetrahydrofuran / -25 °C 11.1: MnO2 / CH2Cl2 / 3 h / Heating 12.1: 33.6 mg / NaH2PO4; 2-methyl-2-butene; NaClO2 / 2-methyl-propan-2-ol; H2O / 20 °C 13.1: NEt3; 2,4,6-trichlorobenzoyl chloride / tetrahydrofuran / 6 h 13.2: 81 percent / DMAP / tetrahydrofuran; toluene / Heating 14.1: 91 percent / aq. HCl / tetrahydrofuran; H2O / 48 h / 20 °C View Scheme

1.1: 95.8 percent / i-Pr2NEt; Py*SO2 / CH2Cl2; dimethylsulfoxide / 0.25 h / 0 °C 2.1: 97.8 percent / TsOH / methanol / 1 h / 20 °C 3.1: 97.1 percent / PPTS / benzene / Heating 4.1: 89.4 percent / NaHCO3; I2 / acetone; H2O / 0.25 h / 0 °C 5.1: LDA / tetrahydrofuran; hexane / 1 h / -78 °C 5.2: tetrahydrofuran; hexane / -78 - 20 °C 6.1: 2.25 g / TiCl4 / CH2Cl2 / 1 h / -78 °C 7.1: 97 percent / DBU / methanol / 1 h / 0 °C 8.1: BuLi / tetrahydrofuran; hexane / 1 h / -78 °C 8.2: MeCuCNLi / tetrahydrofuran; hexane; diethyl ether / 1 h / -78 °C 8.3: 92.6 percent / tetrahydrofuran; hexane; diethyl ether / 1 h / -78 °C 9.1: 131 mg / (S)-2-methyl-CBS-oxazaborolidine; BH3*Me2S / tetrahydrofuran; toluene / 0.25 h / 0 °C 10.1: 96.4 percent / diethyl ether / 1 h / 0 °C 11.1: 72 percent / Li-naphthalene / tetrahydrofuran / -25 °C 12.1: MnO2 / CH2Cl2 / 3 h / Heating 13.1: 33.6 mg / NaH2PO4; 2-methyl-2-butene; NaClO2 / 2-methyl-propan-2-ol; H2O / 20 °C 14.1: NEt3; 2,4,6-trichlorobenzoyl chloride / tetrahydrofuran / 6 h 14.2: 81 percent / DMAP / tetrahydrofuran; toluene / Heating 15.1: 91 percent / aq. HCl / tetrahydrofuran; H2O / 48 h / 20 °C View Scheme

1.1: 97.1 percent / PPTS / benzene / Heating 2.1: 89.4 percent / NaHCO3; I2 / acetone; H2O / 0.25 h / 0 °C 3.1: LDA / tetrahydrofuran; hexane / 1 h / -78 °C 3.2: tetrahydrofuran; hexane / -78 - 20 °C 4.1: 2.25 g / TiCl4 / CH2Cl2 / 1 h / -78 °C 5.1: 97 percent / DBU / methanol / 1 h / 0 °C 6.1: BuLi / tetrahydrofuran; hexane / 1 h / -78 °C 6.2: MeCuCNLi / tetrahydrofuran; hexane; diethyl ether / 1 h / -78 °C 6.3: 92.6 percent / tetrahydrofuran; hexane; diethyl ether / 1 h / -78 °C 7.1: 131 mg / (S)-2-methyl-CBS-oxazaborolidine; BH3*Me2S / tetrahydrofuran; toluene / 0.25 h / 0 °C 8.1: 96.4 percent / diethyl ether / 1 h / 0 °C 9.1: 72 percent / Li-naphthalene / tetrahydrofuran / -25 °C 10.1: MnO2 / CH2Cl2 / 3 h / Heating 11.1: 33.6 mg / NaH2PO4; 2-methyl-2-butene; NaClO2 / 2-methyl-propan-2-ol; H2O / 20 °C 12.1: NEt3; 2,4,6-trichlorobenzoyl chloride / tetrahydrofuran / 6 h 12.2: 81 percent / DMAP / tetrahydrofuran; toluene / Heating 13.1: 91 percent / aq. HCl / tetrahydrofuran; H2O / 48 h / 20 °C View Scheme

1.1: 95.9 percent / LiBH4 / diethyl ether; methanol; tetrahydrofuran / 0 °C 2.1: 95.8 percent / i-Pr2NEt; Py*SO2 / CH2Cl2; dimethylsulfoxide / 0.25 h / 0 °C 3.1: 97.8 percent / TsOH / methanol / 1 h / 20 °C 4.1: 97.1 percent / PPTS / benzene / Heating 5.1: 89.4 percent / NaHCO3; I2 / acetone; H2O / 0.25 h / 0 °C 6.1: LDA / tetrahydrofuran; hexane / 1 h / -78 °C 6.2: tetrahydrofuran; hexane / -78 - 20 °C 7.1: 2.25 g / TiCl4 / CH2Cl2 / 1 h / -78 °C 8.1: 97 percent / DBU / methanol / 1 h / 0 °C 9.1: BuLi / tetrahydrofuran; hexane / 1 h / -78 °C 9.2: MeCuCNLi / tetrahydrofuran; hexane; diethyl ether / 1 h / -78 °C 9.3: 92.6 percent / tetrahydrofuran; hexane; diethyl ether / 1 h / -78 °C 10.1: 131 mg / (S)-2-methyl-CBS-oxazaborolidine; BH3*Me2S / tetrahydrofuran; toluene / 0.25 h / 0 °C 11.1: 96.4 percent / diethyl ether / 1 h / 0 °C 12.1: 72 percent / Li-naphthalene / tetrahydrofuran / -25 °C 13.1: MnO2 / CH2Cl2 / 3 h / Heating 14.1: 33.6 mg / NaH2PO4; 2-methyl-2-butene; NaClO2 / 2-methyl-propan-2-ol; H2O / 20 °C 15.1: NEt3; 2,4,6-trichlorobenzoyl chloride / tetrahydrofuran / 6 h 15.2: 81 percent / DMAP / tetrahydrofuran; toluene / Heating 16.1: 91 percent / aq. HCl / tetrahydrofuran; H2O / 48 h / 20 °C View Scheme

1: 70 percent / DEAD; PPh3 / tetrahydrofuran / 25 °C 2: 90 percent / K2CO3 / methanol; H2O / 0 °C View Scheme

1: 60 percent / N-bromosuccinimide (1 equiv) / 23 °C / acetone-water (5:1) 2: 67 percent / 30 percent H2O2 / acetic acid / 4 h / 5 °C 3: 92 percent / 1.15 equiv Bu3SnH / 0.2 equiv bisazoisobutyronitrile / benzene / 24 h / Heating 4: 1.) dimethyl sulfoxide (1.1 equiv), (CF3CO)2O / 1.) CH2Cl2, -65 deg C, 2.) Et3N, 25 deg C, 1 h 5: K2CO3 / dimethylformamide / 48 h / 23 °C 6: 1.) CpZrHCl, 2.) Ni(acac)2, diisobutylaluminium hydride / 1.) THF, 0 deg C, 2.) THF, -10 deg C then 0 deg C, 8 h 7: 1.) Li-sec-Bu3BH (L-Selectride), 2.) tosic acid / 1.) THF, -78 deg C, 2 h, 2.) toluene, reflux, 10 h 8: 97 percent / diisopropylethylamine / CH2Cl2 / 10 h / 23 °C 9: 98 percent / i-Bu2AlH / CH2Cl2 / 1.5 h / -78 °C 10: 94 percent / piperidine / acetonitrile / 48 h / 5 °C 11: 90 percent / diisopropylethylamine / CH2Cl2 / 23 °C 12: 87 percent / HOAc, H2O (3:1) / 5 h / 23 °C 13: 93 percent / 0.15 M LiOH / 24 h / 23 °C / MeOH, H2O (6:1) 14: 1.) lactonization, 2.) MEM ether cleavage View Scheme

1: 67 percent / 30 percent H2O2 / acetic acid / 4 h / 5 °C 2: 92 percent / 1.15 equiv Bu3SnH / 0.2 equiv bisazoisobutyronitrile / benzene / 24 h / Heating 3: 1.) dimethyl sulfoxide (1.1 equiv), (CF3CO)2O / 1.) CH2Cl2, -65 deg C, 2.) Et3N, 25 deg C, 1 h 4: K2CO3 / dimethylformamide / 48 h / 23 °C 5: 1.) CpZrHCl, 2.) Ni(acac)2, diisobutylaluminium hydride / 1.) THF, 0 deg C, 2.) THF, -10 deg C then 0 deg C, 8 h 6: 1.) Li-sec-Bu3BH (L-Selectride), 2.) tosic acid / 1.) THF, -78 deg C, 2 h, 2.) toluene, reflux, 10 h 7: 97 percent / diisopropylethylamine / CH2Cl2 / 10 h / 23 °C 8: 98 percent / i-Bu2AlH / CH2Cl2 / 1.5 h / -78 °C 9: 94 percent / piperidine / acetonitrile / 48 h / 5 °C 10: 90 percent / diisopropylethylamine / CH2Cl2 / 23 °C 11: 87 percent / HOAc, H2O (3:1) / 5 h / 23 °C 12: 93 percent / 0.15 M LiOH / 24 h / 23 °C / MeOH, H2O (6:1) 13: 1.) lactonization, 2.) MEM ether cleavage View Scheme