1,4-Dioxaspiro[4.5]decan-8-one → 8-[(4-Fluorophenyl)methylene]-1,4-dioxaspiro[4.5]decane

HRID 397162

Reaction equation

HRID 397162 reaction equation
[Cl-].[F:2][C:3]1[CH:8]=[CH:7][C:6]([CH2:9][P+](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=[CH:5][CH:4]=1.CC(C)([O-])C.[K+].[CH2:35]1[O:45][C:38]2([CH2:43][CH2:42][C:41](=O)[CH2:40][CH2:39]2)[O:37][CH2:36]1>C1COCC1>[F:2][C:3]1[CH:4]=[CH:5][C:6]([CH:9]=[C:41]2[CH2:42][CH2:43][C:38]3([O:45][CH2:35][CH2:36][O:37]3)[CH2:39][CH2:40]2)=[CH:7][CH:8]=1

Participants

5

Reactant 3

HCID 5674151,4-Dioxaspiro[4.5]decan-8-oneHCID 2733554(4-Fluorobenzyl)triphenylphosphonium chlorideHCID 23665647Potassium tert-butoxide

Product 1

HCID 121339508-[(4-Fluorophenyl)methylene]-1,4-dioxaspiro[4.5]decaneYield 79.3%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
0 °C

Procedure

To a stirring solution of 4-fluorophenylmethyl triphenylphosphonium chloride (39 g, 96 mmol, Lancaster) in 500 mL of dry THF at −78° C. was added 1 M potassium t-butoxide in THF (106 mL, 106 mmol, Aldrich). The reaction was stirred for 30 min and then warmed to 0° C. The reaction was stirred for 30 min and then 1,4-cyclohexanedione mono-ethylene ketal (15.0 g, 96 mmol, Aldrich) was added. After 30 min, the reaction was warmed to room temperature and allowed to stir overnight. The reaction was heated to reflux for 4 h and then cooled to room temperature. The reaction was quenched with saturated ammonium chloride (500 mL) and ethyl acetate (500 mL). The organic layer was separated, washed with brine, dried over sodium sulfate, and conc in vacuo to a white solid. The solid was purified by flash chromatography (SiO2, 19:1 hexanes:ethyl acetate) to yield 18.9 g of a colorless oil. MS (ESI) 251 (M+H).

Workup

  1. stirringThe reaction was stirred for 30 min
  2. waitAfter 30 min
  3. temperaturethe reaction was warmed to room temperature
  4. stirringto stir overnight
  5. temperatureThe reaction was heated
  6. temperatureto reflux for 4 h
  7. temperaturecooled to room temperature
  8. customThe reaction was quenched with saturated ammonium chloride (500 mL) and ethyl acetate (500 mL)
  9. customThe organic layer was separated
  10. washwashed with brine
  11. dry with materialdried over sodium sulfate
  12. customThe solid was purified by flash chromatography (SiO2, 19:1 hexanes:ethyl acetate)

Sources & evidence

ORD record
ord-157c8a3c8a5045bd96f3c3605b092e44
Source dataset
uspto-grants-2003_08
Patent number
US06608227B1

Linked notes

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