Phenoxyacetylmethylenetriphenylphosphorane → methylene-(2S,5R)-3,3-dimethyl-7-oxo-6-(2-oxo-3-phenoxypropylidene)-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate pivalate

Participants

Reaction Steps

A solution of 3.7 g of methylene-6,7-dioxo-3,3-dimethyl-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate pivalate in 100 ml of benzene is treated at room temperature with 4.7 g of phenoxyacetylmethylenetriphenylphosphorane. After 10 minutes, the reaction mixture is evaporated. The residue is chromatographed on silica gel while eluting with cyclohexane/ethyl acetate (6:4). There is obtained methylene-(2S,5R)-3,3-dimethyl-7-oxo-6-(2-oxo-3-phenoxypropylidene)-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate pivalate as a yellow oil [Rf: 0.44; cyclohexane/ethyl acetate (6:4); NMR (CDCl3), δ (ppm): 1.21 (9H); 1.51 (3H); 1.56 (3H); 4.58 (1H); 5.66 (2H); 5.83 (2H); 6.05 (1H); 6.8-7.45 (6H)].

Provenance & Evidence