Reaktion #49983

Reaktionsgleichung

(3S,4S)-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-4-[(1R)-1-benzyloxycarbonylethyl]azetidin-2-one

t-butyl bromoacetate

sodium hydroxide

→

(3S,4S)-3-[(1R)-1-t-butyl-dimethylsilyloxyethyl]-4-[(1R)-1-benzyloxycarbonylethyl]-1-(t-butyloxycarbonylmethyl)azetidin-2-one

Lösungsmittel

methylene chloride

water

diethyl ether

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe aqueous layer was separated from the organic layer
2. 2
   Extraktionextracted two times with diethyl ether
3. 3
   Waschenwashed with water two times and brine three times
4. 4
   Trocknendried over sodium sulfate
5. 5
   Sonstigeevaporated
6. 6
   SonstigeThe residue was purified by silica gel chromatography

Vorschrift

To a solution of (3S,4S)-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-4-[(1R)-1-benzyloxycarbonylethyl]azetidin-2-one (755 mg) in methylene chloride (10 ml), there were added successively t-butyl bromoacetate (1.88 g), 50% sodium hydroxide (620 mg) and triethylbenzylammonium chloride (220 mg), followed by stirring at room temperature for 2 hours. The reaction mixture was diluted with water and diethyl ether. The aqueous layer was separated from the organic layer and extracted two times with diethyl ether. The extracts were combined with the organic layer, washed with water two times and brine three times, dried over sodium sulfate and evaporated. The residue was purified by silica gel chromatography to give (3S,4S)-3-[(1R)-1-t-butyl-dimethylsilyloxyethyl]-4-[(1R)-1-benzyloxycarbonylethyl]-1-(t-butyloxycarbonylmethyl)azetidin-2-one.

Quelle