Lithium Hexamethyldisilazide → 4-[3-(4,4-Dimethyl-chroman-7-yl)-oct-1-enyl]-benzoic acid methyl ester

HRID 899281Notes

Reaction equation

HRID 899281 reaction equation
[CH3:1][O:2][C:3](=[O:19])[C:4]1[CH:9]=[CH:8][C:7]([CH2:10]P(OCC)(OCC)=O)=[CH:6][CH:5]=1.C[Si]([N-][Si](C)(C)C)(C)C.[Li+].[CH3:30][C:31]1([CH3:49])[C:40]2[C:35](=[CH:36][C:37]([CH:41]([CH2:44][CH2:45][CH2:46][CH2:47][CH3:48])[CH:42]=O)=[CH:38][CH:39]=2)[O:34][CH2:33][CH2:32]1>C1COCC1>[CH3:1][O:2][C:3](=[O:19])[C:4]1[CH:5]=[CH:6][C:7]([CH:10]=[CH:42][CH:41]([C:37]2[CH:36]=[C:35]3[C:40]([C:31]([CH3:49])([CH3:30])[CH2:32][CH2:33][O:34]3)=[CH:39][CH:38]=2)[CH2:44][CH2:45][CH2:46][CH2:47][CH3:48])=[CH:8][CH:9]=1

Participants

5

Reactant 3

HCID 2733832Lithium HexamethyldisilazideHCID 10946061Methyl 4-(diethoxyphosphorylmethyl)benzoateHCID 226406762-(4,4-Dimethyl-chroman-7-yl)-heptanal

Product 1

HCID 692149694-[3-(4,4-Dimethyl-chroman-7-yl)-oct-1-enyl]-benzoic acid methyl esterYield 42.4%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-20 °C

Procedure

A solution of 4-(diethoxyphosphorylmethyl)-benzoic acid methyl ester (0.25 g, 0.87 mmole) in 5 mL of THF at −20° C., was treated with 0.88 mL of 1M lithium bis(trimethylsilyl)amide solution in hexanes. The mixture was stirred at −20° C. for 20 minutes before a solution of 2-(4,4-dimethyl-chroman-7-yl)-heptanal (0.16 g, 0.58 mmole) in 5 mL of THF was added. The reaction mixture was stirred at −20° C. for 30 minutes, at room temperature for 6 hours, quenched by the addition of 10 mL of saturated aqueous ammonium chloride solution and extracted with three 10 mL portions of ethyl acetate. The combined organic extracts were dried over MgSO4, filtered and concentrated in vacuo, to give a yellow oil. The product was purified by flash chromatography (SiO2, 10% ethyl acetate in hexanes) to yield 0.1 g of 4-[3-(4,4-dimethyl-chroman-7-yl)-oct-1-enyl]-benzoic acid methyl ester as a colorless oil.

Workup

  1. additionwas added
  2. customquenched by the addition of 10 mL of saturated aqueous ammonium chloride solution
  3. extractionextracted with three 10 mL portions of ethyl acetate
  4. dry with materialThe combined organic extracts were dried over MgSO4
  5. filtrationfiltered
  6. concentrationconcentrated in vacuo
  7. customto give a yellow oil
  8. customThe product was purified by flash chromatography (SiO2, 10% ethyl acetate in hexanes)

Sources & evidence

ORD record
ord-f207511d177c46feb29bfcf131713b8e
Source dataset
uspto-grants-2008_04
Patent number
US07354931B2

Reaction notes

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