Réaction #49985

Équation de réaction

t-butyl alpha-bromoacetate

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

sodium hydride

phosphoric acid

→

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

Solvants

diethyl ether

dimethylformamide

Conditions de réaction

Traitement

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

Mode opératoire

To a suspension of sodium hydride (31 mg) in dry dimethylformamide (4.3 ml), there were added successively t-butyl alpha-bromoacetate (835 mg) and (3S,4S)-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-4-[(1R)-1-phenylthiocarbonylethyl]azetidin-2-one (0.42 g), and the resultant mixture was stirred at room temperature for 1 hour under a nitrogen stream. The reaction mixture was diluted with diethyl ether and adjusted to pH 6.86 with a phosphoric acid buffer solution. The aqueous layer was separated from the organic layer and extracted with diethyl ether three times. The extracts were combined with the organic layer, washed three times with brine, dried over sodium sulfate and evaporated. The residue was purified by silica gel chromatography to give (3S,4S)-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-4[(1R)-1-phenylthiocarbonylethyl]-1-(t-butyloxycarbonylmethyl)azetidin-2-one.

Source