Methyl acetoacetate → 5-Cyclopentyl-5-hydroxy-9-(4-hydroxy-2,5-dimethyl-phenyl)-3-oxo-non-8-ynoic Acid Methyl Ester

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Reaction Steps

To a freshly prepared solution of LDA (1 M, 2.2 mL, 2.2 mmol) cooled to 0° C. was added methyl acetoacetate (0.12 mL, 1.1 mmol) dissolved in THF (1 mL). After stirring for 30 minutes, 1-cyclopentyl-5-(4-hydroxy-2,5-dimethyl-phenyl)-pent-4-yn-1-one (0.10 g, 0.37 mmol) from Step 1 above dissolved in THF (1 mL) was added. The reaction was stirred for 1 hour, and then warmed to room temperature. After quenching with 10 mL saturated ammonium chloride, the layers were separated. The aqueous layer was extracted with 2×15 mL CH2Cl2, and the organic layers were combined. After drying over Na2SO4, and filtering to remove the solids, the mother liquor was concentrated to an oil. Flash chromatography of the oil gave the desired product (69 mg, 48% yield).

Provenance & Evidence