Citric Acid → HCID 68981864, compound

Participants

Reaction Conditions

Reaction Steps

n-Butyllithium (1.6M in hexanes, 16.0 ml, 25.5 mmol) was added to a solution of diisopropylamine (3.64 ml, 25.5 mmol) and N,N,N′,N′-tetramethylethylenediamine (4.01 ml, 25.5 mmol) in dry THF (36 ml) at −78° C. After 10 min a solution of the ester (622a) (5.10 g, 22.8 mmol) in dry THF (18 ml) was added dropwise, keeping internal temp.<−60° C. The deep red solution was stirred at −78° C. for 40 minutes, then diethyl oxalate (3.10 ml, 22.8 mmol) in THF (18 ml) was added over 5 minutes. The mixture was stirred at −78° C. for 6.5 hours, then treated with 10% citric acid. After warming to room temperature the phases were separated and the aqueous phase was extracted with ethyl acetate. The combined organics were washed with brine, dried and evaporated. Chromatography on silica gel (20-40% ethyl acetate/hexane) gave the title compound (2.05 g, 32%).

Provenance & Evidence