Reaktion #748718

Reaktionsgleichung

(R)-2-benzyl-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester

5-bromo-1-triisopropylsilanyl-1H-indole

tert-butyllithium

→

2-benzyl-2-(1-triisopropylsilanyl-1H-indole-5-carbonyl)-pyrrolidine-1-carboxylic acid tert-butyl ester

Ausbeute 16.5%

Lösungsmittel

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwarmed to room temperature
2. 2
   workup.STIRRINGstirred for two hours
3. 3
   SonstigeThe reaction mixture was quenched by the addition of saturated aqueous NH4Cl (20 mL)
4. 4
   Extraktionthen extracted with EtOAc
5. 5
   WaschenThe combined extracts were washed with brine
6. 6
   Trocknenthen dried (MgSO4)
7. 7
   Filtrationfiltered
8. 8
   Einengenconcentrated in vacuo
9. 9
   SonstigePurification by chromatography (silica, 0-20% EtOAc in hexanes)

Vorschrift

To a stirred solution of 5-bromo-1-triisopropylsilanyl-1H-indole (0.55 g, 1.57 mmol) in THF (10 mL) at −78° C. under nitrogen atmosphere was added tert-butyllithium (2.02 mL of 1.55 M solution in pentanes, 3.13 mmol) dropwise. After one hour, the reaction mixture was added rapidly to a cold (−78° C.) solution of (R)-2-benzyl-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (0.50 g, 3.13 mmol) in THF (10 mL). The reaction mixture was stirred at −78° C. for one hour, then warmed to room temperature and stirred for two hours. The reaction mixture was quenched by the addition of saturated aqueous NH4Cl (20 mL) then extracted with EtOAc. The combined extracts were washed with brine then dried (MgSO4), filtered and concentrated in vacuo. Purification by chromatography (silica, 0-20% EtOAc in hexanes) gave 2-benzyl-2-(1-triisopropylsilanyl-1H-indole-5-carbonyl)-pyrrolidine-1-carboxylic acid tert-butyl ester (0.145 g, 0.259 mmol, 16%) as a colourless gum.

Quelle