Reacción #2254210

Ecuación de reacción

6-oxaspiro[4.5]decan-9-one

methyl cyanoacetate

ammonium acetate

acetic acid

→

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

Disolventes

benzene

water

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroA 100 ml round-bottom flask equipped with a Dean-Stark distillation setup and condenser
2. 2
   Otrocollected in the Dean-Stark (2 hours)
3. 3
   Temperaturacooled
4. 4
   workup.ADDITIONbenzene (30 ml) added
5. 5
   Lavadothe organic washed with water (50 ml)
6. 6
   ExtracciónThe aqueous layer was extracted with CH2Cl2 (3×50 ml)
7. 7
   LavadoThe combined organic phase was washed with sat. NaHCO3 (100 ml), brine (100 ml)
8. 8
   Secadodried (MgSO4)
9. 9
   Filtraciónfiltered
10. 10
    Concentraciónconcentrated
11. 11
    OtroPurified by normal phase SiO2 chromatography (7% to 60% EtOAc/hexanes)

Procedimiento

A 100 ml round-bottom flask equipped with a Dean-Stark distillation setup and condenser was charged with 6-oxaspiro[4.5]decan-9-one (6 g, 39 mmol, which was prepared according to Hanschke, E. Chem. Ber. 1955, 88, 1053), methyl cyanoacetate (4.1 ml, 46.7 mmol), ammonium acetate (780 mg, 10.1 mmol), acetic acid (0.44 ml, 7.8 mmol) and benzene (40 ml). The mixture was refluxed until no more water collected in the Dean-Stark (2 hours), cooled, benzene (30 ml) added and the organic washed with water (50 ml). The aqueous layer was extracted with CH2Cl2 (3×50 ml). The combined organic phase was washed with sat. NaHCO3 (100 ml), brine (100 ml) dried (MgSO4), filtered and concentrated. Purified by normal phase SiO2 chromatography (7% to 60% EtOAc/hexanes) to give methyl 2-cyano-2-[(9Z)-6-oxaspiro[4.5]decan-9-ylidene]acetate as a colorless oil (8.93 g, 97.5%, m/z 235.1 [M+H]+ observed).

Fuente