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

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Reaction Steps

A mixture of KO-tBu (7.4 g, 65.9 mmol) and bromo(methyl)triphenylphosphorane (21.6 g, 60.5 mmol) in ether (100 mL) was refluxed for 0.5 h. Then a solution of 1,4-dioxaspiro[4.5]decan-8-one (6.24 g, 40.0 mmol) in ether (100 mL) was added dropwise during 1.5 h. The reaction mixture was stirred for 2 h, cooled to rt, filtered and the filtrate was concentrated. The residue was purified by silica gel chromatography (EtOAc/hexane) to afford 8-methylene-1,4-dioxaspiro[4.5]decane (1.5 g) as a clear oil. 1H NMR (400 MHz, CDCl3) δ ppm 4.62-4.74 (2H, m), 3.98 (4H, s), 2.30 (4H, dd, J=7.03, 6.02 Hz), 1.66-1.77 (4H, m).

Provenance & Evidence