Reaktion #2349601

Reaktionsgleichung

methylene chloride

3-(tert-butyldimethylsilyloxymethyl)-5-methyl-2,3-dihydrobenzo[1,4]dioxine-6-carboxylic acid

pentafluorophenol

dicyclohexylcarbodiimide

→

3-(tert-butyldimethylsilyloxymethyl)-5-methyl-2,3-dihydrobenzo[1,4]dioxine-6-carboxylic acid pentafluorophenyl ester

Ausbeute 84.0%

Lösungsmittel

ethyl acetate

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeTo a round bottom flask equipped
2. 2
   workup.STIRRINGThis mixture was stirred at room temperature for four hours
3. 3
   workup.STIRRINGstirring
4. 4
   FiltrationThe reaction was filtered
5. 5
   workup.ADDITIONdiluted with ethyl acetate
6. 6
   Waschenwashed once with 1 N HCl, once with saturated aqueous sodium bicarbonate solution, once with saturated sodium chloride
7. 7
   Trocknendried over magnesium sulfate
8. 8
   Filtrationfiltered
9. 9
   Sonstigeevaporated
10. 10
    Sonstigeto give an oil
11. 11
    Sonstigechromatographed on silica gel eluting with hexanes

Vorschrift

To a round bottom flask equipped with magnetic stirring and a nitrogen inlet was added 3-(tert-butyldimethylsilyloxymethyl)-5-methyl-2,3-dihydrobenzo[1,4]dioxine-6-carboxylic acid (0.72 g, 2.13 mmol) and ethyl acetate (11 mL). To this was added pentafluorophenol (0.82 g, 2.23 mmol) followed by 1 M dicyclohexylcarbodiimide in methylene chloride (2.34 mL, 2.34 mmol). This mixture was stirred at room temperature for four hours. A few milliliters of water were added and stirring continued for 10 min. The reaction was filtered, diluted with ethyl acetate, washed once with 1 N HCl, once with saturated aqueous sodium bicarbonate solution, once with saturated sodium chloride, dried over magnesium sulfate, filtered and evaporated to give an oil. This oil was flash chromatographed on silica gel eluting with hexanes to give a clear colorless oil, 3-(tert-butyldimethylsilyloxymethyl)-5-methyl-2,3-dihydrobenzo[1,4]dioxine-6-carboxylic acid pentafluorophenyl ester, (0.90 g, 1.78 mmol) in 84% yield. 1H-NMR (300 MHz, CDCl3) δ (ppm): 0.10 (s, 6H), 0.90 (s, 9H), 2.50 (s, 3H), 3.90 (m, 2H), 4.14 (m, 1H), 4.24 (m, 1H), 4.40 (m, 1H), 6.83, (d, 1H), 7.86, (d, 1H); TLC Rf=0.88 (1:1 ethyl acetate/hexane).

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