Réaction #2006465

Équation de réaction

702

4-Carbethoxy-1,6-heptadiene

2,6-dibromophenol

→

703

Rendement 71.1%

(±)-3-Cyclopentenecarboxylic Acid, Ethyl Ester

Rendement 71.1%

Solvants

toluene

toluene

Conditions de réaction

Traitement

1. 1
   TempératureThe resulting suspension was heated
2. 2
   Températureat reflux under nitrogen for 1 h
3. 3
   Autrethe solvent was evaporated in vacuo
4. 4
   Autredried in vacuo for 30 min
5. 5
   TempératureAfter being cooled to r.t.
6. 6
   Filtrationthe mixture was filtered through a celite
7. 7
   Lavagethe celite was rinsed with t-BuOMe
8. 8
   LavageThe combined filtrates were washed with 1% NaOH soln
9. 9
   Concentrationwater, and brine, and concentrated by evaporation at reduced pressure
10. 10
    workup.DISTILLATIONThe residue was distilled (37-38° C./1 Torr)

Mode opératoire

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).

Source