Acetic Acid → 4-((Tert-butyldimethylsilyl)oxy)-4-methylpent-2-ynal

HRID 275510Notes

Reaction equation

HRID 275510 reaction equation
[CH3:1][C:2]([Si:5]([O:8][C:9]([CH3:13])([CH3:12])[C:10]#[CH:11])([CH3:7])[CH3:6])([CH3:4])[CH3:3].C([Li])CCC.CN(C)[CH:21]=[O:22].C(O)(=O)C>O1CCCC1.O.CCCCCC>[CH3:4][C:2]([Si:5]([CH3:6])([CH3:7])[O:8][C:9]([CH3:13])([CH3:12])[C:10]#[C:11][CH:21]=[O:22])([CH3:1])[CH3:3]

Participants

8

Reactant 4

HCID 176Acetic AcidHCID 6228DimethylformamideHCID 11084826Silane, (1,1-dimethylethyl)[(1,1-dimethyl-2-propynyl)oxy]dimethyl-HCID 178418339Butyllithium

Product 1

HCID 108896204-((Tert-butyldimethylsilyl)oxy)-4-methylpent-2-ynalYield 85.5%

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 8028TetrahydrofuranSolventHCID 8058HexaneSolvent

Conditions

Temperature
-20 °C

Procedure

To a solution of 50.0 g (252 mmol) (1,1-dimethylethyl)[(1,1-dimethyl-2-propynyl)oxy]dimethylsilane in 200 mL of tetrahydrofuran (THF) at -70° C. was added 112 mL (280 mmol) of 2.5M butyl lithium (BuLi) in hexanes dropwise over 25 min., keeping the temperature below -55° C. The mixture was stirred for 5 minutes. Then, 50 mL of dimethylformamide (DMF) was added dropwise over 10 minutes. After 15 minutes, the reaction was quenched by the addition of 32 mL of acetic acid (560 mmol). After the mixture was allowed to warm to -20° C., 200 mL of hexane and 200 mL of water were added. The aqueous layer was back-extracted with 100 mL of hexane. The combined organic layers were washed with 200 mL of saturated aqueous NH4Cl solution and then with 200 mL of brine. After drying over sodium sulfate, the solution was concentrated to dryness. Then the residue was distilled through a 10-cm Vigreaux column to give 48.8 g (85.5% yield) of 4-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-4-methyl-2-pentynal: bp 50° C. (0.5 mm Hg).

Workup

  1. customthe temperature below -55° C
  2. waitAfter 15 minutes
  3. extractionThe aqueous layer was back-extracted with 100 mL of hexane
  4. washThe combined organic layers were washed with 200 mL of saturated aqueous NH4Cl solution
  5. dry with materialAfter drying over sodium sulfate
  6. concentrationthe solution was concentrated to dryness
  7. distillationThen the residue was distilled through a 10-cm Vigreaux column

Sources & evidence

ORD record
ord-669a2039c47c48b286fc42fd6ee4f6a7
Source dataset
uspto-grants-1995_02
Patent number
US05393900

Reaction notes

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