Reacción #2006465

Ecuación de reacción

702

4-Carbethoxy-1,6-heptadiene

2,6-dibromophenol

→

703

Rendimiento 71.1%

(±)-3-Cyclopentenecarboxylic Acid, Ethyl Ester

Rendimiento 71.1%

Disolventes

toluene

toluene

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThe resulting suspension was heated
2. 2
   Temperaturaat reflux under nitrogen for 1 h
3. 3
   Otrothe solvent was evaporated in vacuo
4. 4
   Otrodried in vacuo for 30 min
5. 5
   TemperaturaAfter being cooled to r.t.
6. 6
   Filtraciónthe mixture was filtered through a celite
7. 7
   Lavadothe celite was rinsed with t-BuOMe
8. 8
   LavadoThe combined filtrates were washed with 1% NaOH soln
9. 9
   Concentraciónwater, and brine, and concentrated by evaporation at reduced pressure
10. 10
    workup.DISTILLATIONThe residue was distilled (37-38° C./1 Torr)

Procedimiento

A flame-dried 500 mL flask was charged with 2,6-dibromophenol (1.20 g, 4.76 mmol), tungsten oxychloride (0.813 g, 2.38 mmol), and anhydrous toluene (25 mL). The resulting suspension was heated at reflux under nitrogen for 1 h, and then the solvent was evaporated in vacuo. The solid residue was broken up with a spatula and dried in vacuo for 30 min. To the residue were added toluene (160 mL), Et4Pb (1.54 g, 4.76 mL), and 702 (22 g, 131.0 mmol). The mixture was heated at 90° C. under nitrogen for 1.5 h. After being cooled to r.t., the mixture was filtered through a celite, and the celite was rinsed with t-BuOMe. The combined filtrates were washed with 1% NaOH soln, water, and brine, and concentrated by evaporation at reduced pressure. The residue was distilled (37-38° C./1 Torr) to give 13.06 g (71%) of 703 as a colorless liquid. 1H NMR (400 MHz, CDCl3) δ 5.67 (s, 2H, CH═CH), 4.14 (q, 2H, J=7.2 Hz, OCH2), 3.11 (pentuplet, J=7.6 Hz, 1H, CH), 2.65 (d, J=7.6 Hz, 4H, 2CH2), 1.27 (t, J=7.2 Hz, 3H, CH3).

Fuente