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 tetrahydrofuran (36 mL) at −78° C. After 10 min a solution of the ester (17a, 5.10 g, 22.8 mmol) in dry tetrahydrofuran (18 mL) was added dropwise, keeping the internal temperature <−60° C. The deep red solution was stirred at −78° C. for 40 min, then diethyl oxalate (3.10 mL, 22.8 mmol) in tetrahydrofuran (18 mL) was added over 5 min. 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 organic phases 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