Sodium hydride → ethyl[5,5-dimethyltetrahydro-1'H-spiro[1,3-dioxane-2,2'-pentalen]-5'(3'H)-ylidene]ethanoate

HRID 410478Notes

Reaction equation

[H-].[Na+].[CH3:3][C:4]1([CH3:18])[CH2:17][O:16][C:7]2([CH2:14][CH:13]3[CH:9]([CH2:10][C:11](=O)[CH2:12]3)[CH2:8]2)[O:6][CH2:5]1>C1COCC1>[CH2:5]([O:6][C:7](=[O:16])[CH:8]=[C:11]1[CH2:12][CH:13]2[CH:9]([CH2:8][C:7]3([O:16][CH2:17][C:4]([CH3:18])([CH3:3])[CH2:5][O:6]3)[CH2:14]2)[CH2:10]1)[CH3:4]

Participants

Conditions

Temperature: 0 °C

Procedure

Sodium hydride (60% dispersion in mineral oil, 134 mg, 3.34 mmol) was suspended in THF (2 mL) and cooled to 0° C. Triethylphopsphonoacetate (0.55 g, 2.45 mmol) was added dropwise and the mixture was stirred at 0° C. for 30 min. The product of Step 1 (500 mg, 2.229 mmol) was added dropwise as a solution in THF (0.5 mL) and the reaction mixture was stirred 16 hrs while warming from 0° C. to room temperature. The mixture was partitioned between EtOAc and water, the organic layer dried over Na2SO4, concentrated under reduced pressure and the residue was purified by flash chromatography (7 to 60% EtOAc in hexanes) to give ethyl[5,5-dimethyltetrahydro-1′H-spiro[1,3-dioxane-2,2′-pentalen]-5′(3′H)-ylidene]ethanoate (460 mg, 1.563 mmol, 70.1% yield) as a colorless oil. MS ESI: [M+Na]+ m/z 295.7.

Workup

additionTriethylphopsphonoacetate (0.55 g, 2.45 mmol) was added dropwise
stirringthe reaction mixture was stirred 16 hrs
temperaturewhile warming from 0° C. to room temperature
customThe mixture was partitioned between EtOAc and water
dry with materialthe organic layer dried over Na2SO4
concentrationconcentrated under reduced pressure
customthe residue was purified by flash chromatography (7 to 60% EtOAc in hexanes)

Sources & evidence

ORD record: ord-657ffa2ee19842b98e26663c795a45a5
Source dataset: uspto-grants-2014_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08759366B2

Reaction notes

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