Diethyl [2-oxo-3-(triphenylphosphoranylidene)propyl]phosphonate → methylene-(2S,5R)-6-[(Z)-acetonylidene]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate pivalate

Participants

Reaction Steps

A solution of 1.0 g of methylene-6,7-dioxo-3,3-dimethyl-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate pivalate in 30 ml of benzene is treated at room temperature with 1.8 g of diethoxyphosphinylacetylmethylenetriphenylphosphorane. After 10 minutes, the reaction mixture is evaporated. The residue is chromatographed on silica gel while eluting with ethyl acetate. There is obtained methylene-(2S,5R)-6-[3-(diethoxyphosphinyl)-2-oxopropylidene]-3,3-dimethyl-7-oxo-4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylate pivalate as a yellow oil [Rf: 0.35; ethyl acetate; NMR (CDCl3), δ (ppm): 1.23 (9H); 1.36 (3H); 1.51 (3H); 1.59 (3H); 3.12 and 3.42 (2H, P-CH2); 4.21 (4H); 4.63 (1H); 5.90 (2H): 6.08 (1H); 6.82 (1H)].

Provenance & Evidence