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

Temperature

0 °C

To a solution of methyl triphenylphosphonium bromide (13.7 g, 38 mmol) in 1,4-dioxane (60 mL) was added potassium tert-butoxide (4.3 g, 38 mmol). The resulting yellow mixture was cooled to 0° C. in an ice-water bath and 1,4-dioxaspiro[4.5]decan-8-one (5 g, 32 mmol) was added slowly over 15 min as a solution in 1,4-dioxane (15 mL) via dropping funnel. The reaction was let stir and warm to rt over 1 h. The resulting brown-yellow reaction mixture was partitioned between methyl tert-butyl ether and saturated aqueous NH4Cl solution. The aqueous phase was extracted with methyl tert-butyl ether. The combined organic phases were washed with a saturated aqueous NaCl solution, dried over MgSO4, filtered and concentrated by rotary evaporation in vacuo to ˜20 mL. The resultant beige suspension was diluted with heptane and filtered. The filtrated was concentrated by rotary evaporation in vacuo to afford ˜7 g of crude 8-methylene-1,4-dioxaspiro[4.5]decane as a yellow liquid containing residual heptane.

1. temperaturewarm to rt over 1 h
2. customThe resulting brown-yellow reaction mixture was partitioned between methyl tert-butyl ether and saturated aqueous NH4Cl solution
3. extractionThe aqueous phase was extracted with methyl tert-butyl ether
4. washThe combined organic phases were washed with a saturated aqueous NaCl solution
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated by rotary evaporation in vacuo to ˜20 mL
8. additionThe resultant beige suspension was diluted with heptane
9. filtrationfiltered
10. concentrationThe filtrated was concentrated by rotary evaporation in vacuo

ORD record

ord-2968633b527f4cdbbc28acd32f420b87

Source dataset

uspto-grants-2015_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08993619B2