Reacción #44021

Ecuación de reacción

Boron trifluoride dimethyl etherate

Ethyl 1-(4-chlorophenylsulfonyl)-4-oxo-1,2,3,4-tetrahydropyridine-2-carboxylate

ethyl 1-(4-chlorophenylsulfonyl)-4-oxo-1,2,3,4-tetrahydropyridine-2-carboxylate

SMe2

ethylmagnesium bromide

→

oil

Rendimiento 88.9%

ethyl 1-(4-chlorophenylsulfonyl)-6-ethyl-4-oxopiperidine-2-carboxylate

Rendimiento 88.9%

Disolventes

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.STIRRINGthe mixture stirred for 5 minutes
2. 2
   Temperaturawhile maintaining −78° C. bath temperature
3. 3
   workup.STIRRINGThe reaction was stirred for 4 hours
4. 4
   Otroquenched with a 1:1 solution of 2% NH4Cl/NH4OH
5. 5
   workup.ADDITIONAn equal amount of EtOAc and water was added
6. 6
   Filtraciónthe mixture was filtered
7. 7
   Otroto remove solids
8. 8
   OtroThe layers were separated
9. 9
   Extracciónthe aqueous layer was extracted with two more portions of EtOAc
10. 10
    Secadodried over Na2SO4
11. 11
    Concentraciónconcentrated

Procedimiento

CuBr2.SMe2 (19.13 g, 93.1 mmol) was placed into a flame-dried flask along with THF (250 ml). The mixture was cooled to −78° C. and ethylmagnesium bromide (31 ml, 3.0 M in ether, 93.1 mmol) was added slowly. The reaction was stirred for 45 minutes under nitrogen. Boron trifluoride dimethyl etherate was added (11.7 ml, 93,1 mmol) and the mixture stirred for 5 minutes. Ethyl 1-(4-chlorophenylsulfonyl)-4-oxo-1,2,3,4-tetrahydropyridine-2-carboxylate (103; 8.0 g, 23.3 mmol) was added via syringe pump over a 2 hour period while maintaining −78° C. bath temperature. The reaction was stirred for 4 hours and quenched with a 1:1 solution of 2% NH4Cl/NH4OH. An equal amount of EtOAc and water was added and the mixture was filtered to remove solids. The layers were separated and the aqueous layer was extracted with two more portions of EtOAc. The organic layers were combined and dried over Na2SO4 and concentrated to yield a colorless oil (7.74 g). The material was purified by column chromatography using EtOAc/hexanes gradients to yield 5.84 g (67%) of a mixture of cis/trans (4:96) isomers.

Fuente