Water → Tert.-butyl 2-chloro-3-cyclopentyl-2,3-epoxy-butanoate

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Reaction Conditions

Reaction Steps

A mixture of 12.3 g of cyclopentylmethyl ketone and 18.5 g of tert.-butyl dichloroacetate was cooled to -30° C with stirring under an inert atmosphere and a solution of 12.2 g of potassium tert.-butylate in 60 ml of tetrahydrofuran was added thereto at the said temperature. After returning to room temperature, hexane and water were added and the organic phase was separated, washed with water and dried over magnesium sulfate. The solvents were evaporated off to leave an oily residue of tert.-butyl 2-chloro-3-cyclopentyl-2,3-epoxy-butanoate. 26.5 g of the latter product was added to a solution of 3 g of lithium carbonate and 20 g of lithium bromide in 100 ml of hexamethylphosphorotriamide and after stirring for 1 hour at room temperature, petroleum ether and water were added thereto. The organic phase was washed with water, dried over magnesium sulfate and filtered. The solvent was evaporated to obtain an oily residue which was tert.-butyl 3-cyclopentyl-2-oxo-3-butenoate which was used as is for the next step.

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