oxalic acid in pentane 12 h; Ambient temperature;

1: 1 M DIBAL / diethyl ether / Ambient temperature 2: tetrahydrofuran / 12 h / Ambient temperature 3: N-chlorosuccinimide / CH2Cl2 / 0.25 h 4: potassium superoxide / 18-crown-6 / diethyl ether / Ambient temperature 5: 63 percent / oxalic acid / pentane / 12 h / Ambient temperature View Scheme

1: oxalyl chloride / CH2Cl2 / 14 h 2: 30 percent NH4OH 3: 1.) triethyloxonium tetrafluoroborate / 1.) 1,2-dichloroethane, 22 h; 2.) 1,2-dichloroethane, 24 h, reflux 4: 1.) Mg / 1.) ether, 1 h; 2.) ether, THF, 24 h 5: 1 M DIBAL / diethyl ether / Ambient temperature 6: tetrahydrofuran / 12 h / Ambient temperature 7: N-chlorosuccinimide / CH2Cl2 / 0.25 h 8: potassium superoxide / 18-crown-6 / diethyl ether / Ambient temperature 9: 63 percent / oxalic acid / pentane / 12 h / Ambient temperature View Scheme

1: 1.) triethyloxonium tetrafluoroborate / 1.) 1,2-dichloroethane, 22 h; 2.) 1,2-dichloroethane, 24 h, reflux 2: 1.) Mg / 1.) ether, 1 h; 2.) ether, THF, 24 h 3: 1 M DIBAL / diethyl ether / Ambient temperature 4: tetrahydrofuran / 12 h / Ambient temperature 5: N-chlorosuccinimide / CH2Cl2 / 0.25 h 6: potassium superoxide / 18-crown-6 / diethyl ether / Ambient temperature 7: 63 percent / oxalic acid / pentane / 12 h / Ambient temperature View Scheme

1: 1.) Mg / 1.) ether, 1 h; 2.) ether, THF, 24 h 2: 1 M DIBAL / diethyl ether / Ambient temperature 3: tetrahydrofuran / 12 h / Ambient temperature 4: N-chlorosuccinimide / CH2Cl2 / 0.25 h 5: potassium superoxide / 18-crown-6 / diethyl ether / Ambient temperature 6: 63 percent / oxalic acid / pentane / 12 h / Ambient temperature View Scheme

1: tetrahydrofuran / 12 h / Ambient temperature 2: N-chlorosuccinimide / CH2Cl2 / 0.25 h 3: potassium superoxide / 18-crown-6 / diethyl ether / Ambient temperature 4: 63 percent / oxalic acid / pentane / 12 h / Ambient temperature View Scheme

1: N-chlorosuccinimide / CH2Cl2 / 0.25 h 2: potassium superoxide / 18-crown-6 / diethyl ether / Ambient temperature 3: 63 percent / oxalic acid / pentane / 12 h / Ambient temperature View Scheme

1: potassium superoxide / 18-crown-6 / diethyl ether / Ambient temperature 2: 63 percent / oxalic acid / pentane / 12 h / Ambient temperature View Scheme

1: 30 percent NH4OH 2: 1.) triethyloxonium tetrafluoroborate / 1.) 1,2-dichloroethane, 22 h; 2.) 1,2-dichloroethane, 24 h, reflux 3: 1.) Mg / 1.) ether, 1 h; 2.) ether, THF, 24 h 4: 1 M DIBAL / diethyl ether / Ambient temperature 5: tetrahydrofuran / 12 h / Ambient temperature 6: N-chlorosuccinimide / CH2Cl2 / 0.25 h 7: potassium superoxide / 18-crown-6 / diethyl ether / Ambient temperature 8: 63 percent / oxalic acid / pentane / 12 h / Ambient temperature View Scheme

1: p-TsOH / toluene / Heating 2: 1.) ether, hexane, -78 deg C to r.t., 3 h, 2.) acid hydrolysis View Scheme