Phosphate → HCID 131719087, compound

Participants

Reaction Conditions

Reaction Steps

A solution of 1.2 g of 3-{(2R)-2-[(3S,4R)-1-allyloxycarbonylmethyl-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-2-oxoazetidin-4-yl]propionyl}-spiro[2,3-dihydro-4H-1,3-benzoxazine-2,1'-cyclohexan]-4-one in 6 ml of tetrahydrofuran is added dropwise to 4.4 ml of 1 M sodium bis(trimethylsilyl)amide solution (solvent: tetrahydrofuran) at a temperature from -20° C. to -30° C. during one minute. 261 mg of trimethylsilyl chloride are added thereto at -50° C. and the mixture is stirred for 2 minutes. Then, 645 mg of diphenylphosphoryl chloride are added thereto at -50° C. and the mixture is stirred for 2 hours at 0° C. The reaction mixture is poured into 50 ml of 0.2 M phosphate buffer (pH 7.0) and the mixture is extracted with ethyl acetate. The extract is washed, dried and evaporated to remove the solvent. Isopropyl ether is added to the residue and the resulting precipitates of 355 mg of spiro[2,3-dihydro-4H-1,3-benzoxazine-2,1'-cyclohexan]-4-one are removed by filtration. The filtrate is condensed to obtain 1.04 g of (1R,5R,6S)-6-[(1R)-1-t-butyldimethylsilyloxyethyl]-1-methyl-2-diphenylphosphoryloxy-carbapen-2-em-3-carboxylic acid.allyl ester as syrup.

Provenance & Evidence