Réaction #49983

Équation de réaction

(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

Solvants

methylene chloride

water

diethyl ether

Conditions de réaction

Traitement

1. 1
   AutreThe aqueous layer was separated from the organic layer
2. 2
   Extractionextracted two times with diethyl ether
3. 3
   Lavagewashed with water two times and brine three times
4. 4
   Séchagedried over sodium sulfate
5. 5
   Autreevaporated
6. 6
   AutreThe residue was purified by silica gel chromatography

Mode opératoire

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.

Source