Réaction #2254221

Équation de réaction

6-oxaspiro[4.5]decan-9-one

methylcyanoacetate

ammonium acetate

acetic acid

→

methyl 2-cyano-2-[6-oxaspiro[4.5]decan-9-ylidene]acetate

Rendement 87.8%

Solvants

hexane

benzene

EtOAc

benzene

Conditions de réaction

Traitement

1. 1
   Températurewas heated
2. 2
   Températureat reflux in a 250 ml round bottom flask
3. 3
   Autreequipped with a Dean-Stark and a reflux condenser
4. 4
   TempératureAfter cooling
5. 5
   Autrethe layer was separated
6. 6
   Lavagethe organic was washed by water (120 ml)
7. 7
   Extractionthe aqueous layer was extracted by CH2Cl2 (3×120 ml)
8. 8
   LavageThe combined organic was washed with sat'd NaHCO3, brine
9. 9
   Autredried
10. 10
    Concentrationconcentrated
11. 11
    Autrethe residual was purified by flash chromatography (340 g silica gel column, eluted by EtOAc in hexane: 5% EtOAc, 2 CV; 5-25%, 14 CV; 25-40%, 8 CV)
12. 12
    Autregave
13. 13
    workup.ADDITIONa mixture of E and Z isomers

Mode opératoire

A mixture of 6-oxaspiro[4.5]decan-9-one (13.74 g, 89.1 mmol), methylcyanoacetate (9.4 ml, 106.9 mmol), ammonium acetate (1.79 g, 26.17 mmol) and acetic acid (1.02 ml, 17.8 mmol) in benzene (75 ml) was heated at reflux in a 250 ml round bottom flask equipped with a Dean-Stark and a reflux condenser. After 3 h, TLC (25% EtOAc in hexane, PMA stain) showed the reaction was completed. After cooling, benzene (50 ml) was added and the layer was separated, the organic was washed by water (120 ml) and the aqueous layer was extracted by CH2Cl2 (3×120 ml). The combined organic was washed with sat'd NaHCO3, brine, dried and concentrated and the residual was purified by flash chromatography (340 g silica gel column, eluted by EtOAc in hexane: 5% EtOAc, 2 CV; 5-25%, 14 CV; 25-40%, 8 CV) gave a mixture of E and Z isomers: methyl 2-cyano-2-[6-oxaspiro[4.5]decan-9-ylidene]acetate (18.37 g, 87.8% yield, m/z 236.0 [M+H]+ observed) as a clear oil.

Source