Methyl chloroformate → Dimethyl 3-butylcyclobutane-1,1-dicarboxylate
Reaction equation
[CH3:1][O:2][C:3]([CH:5]1[CH2:8][CH:7]([CH2:9][CH2:10][CH2:11][CH3:12])[CH2:6]1)=[O:4].C(NC(C)C)(C)C.[Li].Cl[C:22]([O:24][CH3:25])=[O:23]>C1COCC1>[CH3:1][O:2][C:3]([C:5]1([C:22]([O:24][CH3:25])=[O:23])[CH2:6][CH:7]([CH2:9][CH2:10][CH2:11][CH3:12])[CH2:8]1)=[O:4]Participants
Procedure
A solution of 3-butyl-cyclobutanecarboxylic acid methyl ester (7.75 g, 45.6 mmol) in THF (30 mL) was added dropwise to a solution of lithium diisopropylamine (7.26 g, 68.4 mmol) in THF (70 mL) at −78° C. After stirring for 1.5 h at the same temperature, methyl chloroformate (6.46 g, 68.4 mmol) was added slowly and the mixture was allowed to warm to room temperature. After 18 h the reaction mixture was quenched with saturated aqueous NH4Cl solution (200 mL) and the aqueous residue was extracted with EtOAc (75 mL×5). The combined organic layers were dried (MgSO4). After removal of the solvent under reduced pressure, purification by flash column chromatography using an eluting system of hexane/EtOAc (95:5) yielded the title compound as a clear yellow oil (8.37 g, 81%). MH+229.
Workup
- additionwas added slowly
- customAfter 18 h the reaction mixture was quenched with saturated aqueous NH4Cl solution (200 mL)
- extractionthe aqueous residue was extracted with EtOAc (75 mL×5)
- dry with materialThe combined organic layers were dried (MgSO4)
- customAfter removal of the solvent
- customunder reduced pressure, purification by flash column chromatography
Sources & evidence
- ORD record
- ord-a68bb5d5260b4ab78650a14317195fb6
- Source dataset
- uspto-grants-2008_02
- Patent number
- US07332485B2
Reaction notes
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