반응 #46633

반응 방정식

product

(S)-tert-butyl 2-(2-(4-bromophenyl)-2-oxoethylcarbamoyl)pyrrolidine-1-carboxylate

PPh3

diisopropylethylamine

hexachloroethane

PPh3

hexachloroethane

→

(S)-tert-butyl 2-(5-(4-bromophenyl)oxazol-2-yl)pyrrolidine-1-carboxylate

수율 63.3%

용매

CH3CN

—

hexanes

ethyl acetate

반응 조건

후처리

1. 1
   workup.STIRRINGstirring
2. 2
   workup.WAITcontinued for 4 hours
3. 3
   기타The solvent was removed in vacuo
4. 4
   workup.ADDITIONthe residue diluted with ethyl acetate-H2O
5. 5
   기타the layers separated
6. 6
   추출The aqueous phase was extracted twice with ethyl acetate
7. 7
   세척the combined organic layers were washed (H2O, brine)
8. 8
   건조dried (Na2SO4)
9. 9
   여과filtered
10. 10
    기타The solvent was removed in vacuo
11. 11
    기타the residue purified by flash column chromatography (3:1 hexanes:ethyl acetate)

실험 절차

To a solution of the product of Step 1 (1.00 g, 2.43 mmol), PPh3 (1.00 g, 3.71 mmol) and diisopropylethylamine (1.3 mL, 7.28 mmol) in CH3CN (30 mL) was added hexachloroethane (0.812 g, 3.43 mmol) as a solid, portion-wise. The mixture was allowed to stir for 12 hours. TLC (3:1 hexanes:ethyl acetate) indicated the presence of starting material. Therefore, additional PPh3 (0.65 g, 2.43 mmol) and hexachloroethane (0.575 g, 2.43 mmol) were added and stirring continued for 4 hours. The solvent was removed in vacuo, the residue diluted with ethyl acetate-H2O and the layers separated. The aqueous phase was extracted twice with ethyl acetate and the combined organic layers were washed (H2O, brine), dried (Na2SO4), and filtered. The solvent was removed in vacuo and the residue purified by flash column chromatography (3:1 hexanes:ethyl acetate) to provide (S)-tert-butyl 2-(5-(4-bromophenyl)oxazol-2-yl)pyrrolidine-1-carboxylate (0.605 g, 63%). 1HNMR (400 MHz, DMSO-d6) δ 7.60-7.68 (m, 5H), 4.80-4.91 (m, 1H), 3.46-3.51 (m, 1H), 3.33-3.39 (m, 1H), 2.18-2.31 (m, 1H), 1.84-1.99 (m, 3H), 1.36 (s, 4H), 1.15 (s, 5H). LCMS: Anal. Calcd. for C18H21BrN2O3: 392. found: 393 (M+H)+.

출처