반응 #89730

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Lithium hexamethyldisilazide

1-benzyl 4-methyl(2S)-2-[benzyl((2R)-2-(1-ethoxyethoxy)-3-[(4-methylphenyl)sulfonyl]oxypropyl)amino]succinate

toluene

→

product

수율 78.2%

2-benzyl 3-methyl(2S,3S,5S)-1-benzyl-5-(1-ethoxyethoxy)piperidine-2,3-dicarboxylate

수율 78.2%

용매

tetrahydrofuran

tetrahydrofuran

반응 조건

후처리

1. 1
   온도to warm up to at 0 Celsius gradually
2. 2
   workup.STIRRINGstirred at 0 Celsius for 30 min
3. 3
   기타After quenched with aq ammonium chloride
4. 4
   추출the mixture was extracted with ethyl acetate
5. 5
   세척The combined organic layers were washed with water, brine
6. 6
   건조dried (sodium sulfate)
7. 7
   농축concentrated
8. 8
   기타to dry
9. 9
   기타The residue was purified on silica gel column
10. 10
    세척eluting with 0 to 20% EtOAc in hexane

실험 절차

To a solution of 1-benzyl 4-methyl(2S)-2-[benzyl((2R)-2-(1-ethoxyethoxy)-3-[(4-methylphenyl)sulfonyl]oxypropyl)amino]succinate (34.30 g, 0.05464 mol) in a mixture of tetrahydrofuran (90.0 mL, 1.11 mol) and toluene (470.0 mL, 4.412 mol) at −78 Celsius was added 1.00 M of Lithium hexamethyldisilazide in tetrahydrofuran (65.6 mL). The resulting mixture was stirred at −78 Celsius overnight, and then allowed to warm up to at 0 Celsius gradually and stirred at 0 Celsius for 30 min. After quenched with aq ammonium chloride, the mixture was extracted with ethyl acetate. The combined organic layers were washed with water, brine, and dried (sodium sulfate), and concentrated to dry. The residue was purified on silica gel column, eluting with 0 to 20% EtOAc in hexane, to yield the cyclized product (19.47 g, 78.2%). MS (ESI): (M+H)+=456.0.

출처