Reaktion #409708

Reaktionsgleichung

NH4Cl

ethyl bromoacetate

13-7

(5(R)-methyl-2-oxo-pyrrolidin-3(S)-yl)-carbamic acid tert-butyl ester

sodium bis(trimethylsilyl)amide

→

13-8

(3(S)-tert-butoxycarbonylamino-5(R)-methyl-2-oxo-pyrrolidin-1-yl)-acetic acid ethyl ester

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITAfter an additional 20 minutes
2. 2
   SonstigeThe layers were separated
3. 3
   Waschenthe aqueous layer washed with EtOAc
4. 4
   Trocknenthe combined organic extracts were dried over K2CO3
5. 5
   Sonstigeremoval of the solvent
6. 6
   Sonstigethe residue was chromatographed (silica gel, 40% ethyl acetate/hexanes)

Vorschrift

To a solution of 13-7 (1.83 g, 8.4 mmol) in THF (22 mL) at −78° C. was added sodium bis(trimethylsilyl)amide (9.4 mL, 9.4 mmol; 1M/THF) dropwise. After an additional 20 min, ethyl bromoacetate (1.13 mL, 10.3 mmol) was added dropwise. After an additional 20 minutes, the mixture was allowed to warm to 0° C., and 20 mL sat. aqueous NH4Cl was added. The layers were separated, the aqueous layer washed with EtOAc, and the combined organic extracts were dried over K2CO3. Following evaporative removal of the solvent, the residue was chromatographed (silica gel, 40% ethyl acetate/hexanes) to give 13-8 as a colorless oil.

Quelle