反応 #44021

反応方程式

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

収率 88.9%

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

収率 88.9%

溶媒

THF

反応条件

後処理

1. 1
   workup.STIRRINGthe mixture stirred for 5 minutes
2. 2
   温度while maintaining −78° C. bath temperature
3. 3
   workup.STIRRINGThe reaction was stirred for 4 hours
4. 4
   その他quenched with a 1:1 solution of 2% NH4Cl/NH4OH
5. 5
   workup.ADDITIONAn equal amount of EtOAc and water was added
6. 6
   ろ過the mixture was filtered
7. 7
   その他to remove solids
8. 8
   その他The layers were separated
9. 9
   抽出the aqueous layer was extracted with two more portions of EtOAc
10. 10
    乾燥dried over Na2SO4
11. 11
    濃縮concentrated

実験手順

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.

出典