Trimethyl phosphonoacetate → HCID 18467805, compound

Participants

Reaction Conditions

Reaction Steps

2,5-Dimethyl-3-oxo-2-tetrahydrofuroic acid, t-butyl ester (64 mg, from Reference Example 23, Step D) was dissolved in anhydrous methanol (1 mL) and cooled to −78° C. Potassium bis(trimethylsilyl)amide 0.66 mL) was added dropwise over 10 minutes. After being stirred at 78° C. for 15 minutes, trimethyl phosphonoacetate (65 mg, dissolved in 1.5 mL tetrahydrofuran) was added dropwise over 25 minutes. Upon completion of addition, the cold bath was removed and the mixture was allowed to stir at room temperature for 3 h when TLC (4/1 hexane/ethyl acetate) showed formation of a new spot. At 0° C., the reaction was quenched by addition of 1.5 mL of saturated aqueous ammonium chloride and the product was extracted with ethyl acetate twice, washed with saturated sodium chloride and dried over anhydrous magnesium sulfate. The crude product obtained after filtration and removal of volatiles was flash chromatographed over silica get, using gradient elution (50-10/1 hexane/ethyl acetate) to give 31 mg of the desired compound, homogeneous by TLC (Rf=0.5 in 4/1 hexane/ethyl acetate). The NMR showed that all the diastereomers are present in this sample.

Provenance & Evidence