Réaction #2320129

Équation de réaction

paraformaldehyde

paraformaldehyde

N-methylanilinium trifluoroacetate

diethyl ether

α-tetralone

→

2-methylene-3,4-dihydronaphthalen-1-one

Rendement 92.4%

Solvants

THF

Conditions de réaction

Traitement

1. 1
   TempératureThe solution was heated
2. 2
   Températureat reflux under nitrogen
3. 3
   workup.DISSOLUTIONdissolved
4. 4
   TempératureAfter cooling
5. 5
   AutreThe solvent was separated from the reaction mixture
6. 6
   Lavagewashed with 500 mL of saturated sodium bicarbonate
7. 7
   workup.ADDITIONAdditional diethyl ether was added to the reaction mixture
8. 8
   Autreseparated
9. 9
   Extractionto back extract the aqueous sodium bicarbonate layer
10. 10
    SéchageThe combined organic layers were dried over magnesium sulfate
11. 11
    Concentrationthe solution was then concentrated to a volume of approximately 300 mL
12. 12
    Filtrationfiltered through Celite
13. 13
    AutreComplete evaporation of the ether

Mode opératoire

To a suspension of paraformaldehyde (46.2 g, 1.54 mol) and N-methylanilinium trifluoroacetate (TAMA, 46.2 g, 1.54 mol) in 340 mL of dry THF was added α-tetralone (50 g, 0.342 mol). The solution was heated at reflux under nitrogen with stirring for 4 h, during which time the paraformaldehyde dissolved. After cooling, diethyl ether (700 mL) was added to the reaction mixture. The solvent was separated from the reaction mixture and washed with 500 mL of saturated sodium bicarbonate. Additional diethyl ether was added to the reaction mixture, separated and used to back extract the aqueous sodium bicarbonate layer. The combined organic layers were dried over magnesium sulfate, and the solution was then concentrated to a volume of approximately 300 mL and filtered through Celite. Complete evaporation of the ether yielded 50 g (90%) of crude 2-methylene-3,4-dihydronaphthalen-1-one, which was used immediately for the next reaction to prevent polymerization of the product.

Source