Methanol → (5S)-5-(1,2-Propadienyl)pyrrolidin-2-one

Participants

Reaction Steps

A solution of (5S)-N-((2S)-2-(1,1-dimethylethyl)dimethylsilyloxy)propanoyl)-5-(1,2-propadienyl)pyrrolidin-2-one (2.70 g, 8.7 mmol), K2CO3 (0.6 g, 4.4 mmol), and MeOH (40 mL) was stirred at room temperature for 1.5 hours. The solvent was removed by rotary evaporation (≤30° C.) to give a yellow gum. This gum was dissolved in CH2Cl2 (20 mL), filtered to remove salts and applied to a silica gel plug (50 g). This plug was rinsed with 10% MeOH/CH2Cl2, discarding the initial eluent which contains the chiral auxiliary, to give (5S)-5-(1,2-Propadienyl)pyrrolidin-2-one (1.04 g, 97%) as a clear oil: TLC (Eluent A) Rf =0.45; 1H NMR: δ6.6 (br s, 1 H, NH); 5.17 (ddd, 3J64 ≃4J68 ≃4J68 ≃6.6 Hz, 1 H, H6); 4.88 (d, 4J68 ≃6.7 Hz, 1 H, H8); 4.88 (d, 4J68' =6.4, 1 H, H8'); 4.21 (m, 1 H, H5); 2.35 (m, 3 H, H3, H4, H4'); 1.93 (m, 1 H, H3'); Cl Mass spec: m/z 124 (MH+), 84 (MH+ --C3H4).

Provenance & Evidence