1: 74 percent / diethyl ether / 0.5 h / -100 °C 2: 98 percent / 2,6-lutidine / CH2Cl2 / 0.75 h / -78 °C 3: 1) O3, 2) PPh3 / 1) CH2Cl2, -78 deg C, 30 min, 2) Ch2Cl2, -78 deg C -> room temperature; room temperature, 1 h 4: lithium tri-tert-butoxyaluminohydride / tetrahydrofuran / 1) -78 deg C, 5 min, 2) 0 deg C, 15 min 5: 1.26 g / Et3N, 4-DMAP / CH2Cl2 / 1) 0 deg C, 2 h, 2) 25 deg C, 10 h 6: 1) LDA / 1) THF, -78 deg C, 15 min; -78 deg C -> -40 deg C, 1 h, 2) THF, -78 deg C, 15 min 7: 96 percent / 2,6-lutidine / CH2Cl2 / 2 h / 0 °C 8: 85 percent / camphorsulfonic acid / CH2Cl2; methanol / 0.5 h / 0 - 25 °C 9: 1) (COCl)2, DMSO, 2) Et3N / 1) CH2Cl2, -78 deg C, 30 min, 2) CH2Cl2, -78 deg C -> 0 deg C, 30 min 10: 90 percent / NaClO2, isobutylene, NaH2PO4 / 2-methyl-propan-2-ol; H2O; tetrahydrofuran / 1 h / Ambient temperature View Scheme

1: 74 percent / diethyl ether / 0.5 h / -100 °C 2: 98 percent / 2,6-lutidine / CH2Cl2 / 0.75 h / -78 °C 3: 1) O3, 2) PPh3 / 1) CH2Cl2, -78 deg C, 30 min, 2) Ch2Cl2, -78 deg C -> room temperature; room temperature, 1 h 4: lithium tri-tert-butoxyaluminohydride / tetrahydrofuran / 1) -78 deg C, 5 min, 2) 0 deg C, 15 min 5: 1.26 g / Et3N, 4-DMAP / CH2Cl2 / 1) 0 deg C, 2 h, 2) 25 deg C, 10 h 6: 1) LDA / 1) THF, -78 deg C, 15 min; -78 deg C -> -40 deg C, 1 h, 2) THF, -78 deg C, 15 min View Scheme

1: 74 percent / diethyl ether / 0.5 h / -100 °C 2: 98 percent / 2,6-lutidine / CH2Cl2 / 0.75 h / -78 °C 3: 1) O3, 2) PPh3 / 1) CH2Cl2, -78 deg C, 30 min, 2) Ch2Cl2, -78 deg C -> room temperature; room temperature, 1 h 4: 93 percent / NaClO2, 2-methyl-2-butene, NaH2PO4 / 2-methyl-propan-2-ol; tetrahydrofuran; H2O / 4 h / Ambient temperature 5: 1) LDA / 1) THF, -78 deg C, 15 min; -40 deg C, 0.5 h, 2) THF, -78 deg C, 15 min 6: 2,6-lutidine / CH2Cl2 / 2 h / 0 °C 7: 1.1 g / K2CO3 / methanol / 0.25 h / 25 °C 8: 78 percent / TBAF / tetrahydrofuran / 8 h / 25 °C 9: 1) Et3N, 2,4,6-trichlorobenzoyl chloride, 2) 4-DMAP / 1) THF, 0 deg C, 15 min, 2) toluene, 25 deg C, 0.5 h 10: 92 percent / CF3CO2H / CH2Cl2 / 1) -20 deg C -> 0 deg C, 2) 0 deg C, 1 h View Scheme

1: 88 percent / Bu2BOTf; DIPEA / CH2Cl2 / 1 h / -78 °C 2: 95 percent / 2,6-lutidine / CH2Cl2 / 1 h / 0 °C 3: 76 percent / lithium hydroxide; hydrogen peroxide / tetrahydrofuran; H2O / 4 h / 20 °C 4: 71 percent / borane-dimethyl sulfide; trimethyl borate / tetrahydrofuran / 9 h / 0 - 15 °C 5: 72 percent / imidazole / CH2Cl2 / 3 h / 0 °C View Scheme

1: diethyl methoxycarbonylmethyl-phosphonate With n-butyllithium in tetrahydrofuran; hexane T=0°C; 0.5 h; Inert atmosphere; 2: 2,2-dimethyl-3-oxopentanal in tetrahydrofuran; hexane T=-78 - 20°C;