Spiro[2.5]octane-4,6-dione synthesis

Yield:-

Reaction Conditions:

in tetrahydrofuran;N-methyl-acetamide;

Steps:

H.23 Spiro[2.5]octane-4,6-dione (compound H-C1)

74.5 g of methyl 3-(1-acetylcyclopropyl)propionate (0.32 mol) are dissolved in 1 l of tetrahydrofuran and the solution is treated portionwise with 14.3 g of sodium hydride (55% suspension in oil, 0.32 mol) at room temperature. After 1 hour, the reaction mixture is diluted with 200 ml of dimethylformamide and warmed to 70° C. After 8 hours, tetrahydrofuran is removed in vacuo, and the residue is poured into 2 N hydrochloric acid and extracted with diethyl ether The organic phase is dried over sodium sulfate and concentrated, and column chromatography over silica gel (methylene chloride:ethanol 9:1 as eluent) gives spiro[2.5]octane-4,6-dione in the form of white crystals of melting point 116-118° C.

References:

US2003/40437,2003,A1