Reaktion #2045063

Reaktionsgleichung

(Carbethoxymethylene)triphenyl-phosphorane

campholenic aldehyde

→

ethyl 4-(2,2,3-trimethylcyclopent-3-enyl)but-2-enoate

Ausbeute 89.7%

Lösungsmittel

—

hexanes

methyl tertiary-butyl ether

—

hexanes

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeto give a solution
2. 2
   workup.STIRRINGthen stirred at room temperature for about 24 h
3. 3
   workup.ADDITIONwas added
4. 4
   workup.WAITwas then placed in an ice bath for 30 min
5. 5
   FiltrationThe reaction mixture was then filtered through a plug of filter paper, celite, silica, and sand
6. 6
   Waschenwashed three times
7. 7
   EinengenThe combined eluates were concentrated in vacuo

Vorschrift

To a flame-dried 250 ml round bottom flask campholenic aldehyde (10.0 g, 65.7 mmol) and methyl tertiary-butyl ether (MTBE) (100 ml) were added to give a solution and the flask was slowly cooled to 0° C. in an ice water bath. (Carbethoxymethylene)triphenyl-phosphorane (22.8 g, 66.0 mmol) was slowly added to the solution. The reaction mixture was stirred at 0° C. for 20 min then stirred at room temperature for about 24 h. After the reaction was completed, the reaction mixture was reduced to half its volume in vacuo and 100 ml of hexanes was added. The flask containing the reaction mixture and hexanes was then placed in an ice bath for 30 min. The reaction mixture was then filtered through a plug of filter paper, celite, silica, and sand and washed three times, first with hexanes, then 9:1 and then 1:1 Hexanes/MTBE. The combined eluates were concentrated in vacuo and purifed via flash column chromatography (1:8 Hexanes/Ethyl Acetate (AcOEt)) to give ethyl 4-(2,2,3-trimethylcyclopent-3-enyl)but-2-enoate (13.1 g, 89%) as an oil. The NMR data is indicated below.

Quelle