7-(3-Hydroxy-5-oxo-1-cyclopentenyl)-heptanoic acid ethyl ester → 4-Tert-butoxy-2-(6-carbethoxyhexyl)cyclopent-2-en-1-one

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Reaction Steps

A stirred mixture of 6.35 g. (20 mmoles) of 4-bromo-2-(carbethoxyhexyl)cyclopent-2-en-1-one (Example 94), 3.01 g. (11 moles) of silver carbonate, and 40 ml. of t-butanol is heated at 70° C. for 17 hours. The mixture is cooled and filtered. After evaporation of t-butanol the residue is treated with aq. sodium chloride and extracted with 3:1 ether-hexane. The extract is washed with saturated sodium chloride solution, dried over magnesium sulfate, and concentrated. The crude product is purified by chromatography on silica gel to give, in order of elution: the subject compound as an oil; λ maxMeOH. = 219 mμ (8860); ν max. = 1735 (ester carbonyl group), 1725 ketone carbonyl group), and 1365 cm-1 (tert.-butyl group); and 4-hydroxy-2-(6-carbethoxyhexyl)cyclopent-2-en-1-one also as an oil.

Provenance & Evidence