1,4-Dioxaspiro[4.5]decan-8-one → 8-Methylidene-1,4-dioxaspiro[4.5]decane

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Reaction Steps

A solution of n-BuLi (2.5 M in hexanes, 30 ml, 75 mmol) was slowly added to a suspension of methyltriphenylphosphonium bromide (28.07 g, 79 mmol) in THF (150 ml) at −10° C. After stirring for 1 h, 1,4-dioxaspiro[4.5]decan-8-one (8.01 g, 51.3 mmol) was added. The reaction was warmed to room temperature and stirred for 4 h. The reaction was quenched with sat. aq. NH4Cl and extracted by diethyl ether. The combined organic extracts were dried (Na2SO4), concentrated at 200 mbar and 30° C. The residue was diluted with DCM and hexanes (1:1), and the solid was filtered. The organic extracts were concentrated at 200 mbar and 30° C., followed by silica gel chromatography (EtOAc/hexanes: 0-10%-20% gradient) to afford the title compound.

Provenance & Evidence