Mild and efficient preparation of γ-substituted α,β-unsturated γ-butyrolactones from epoxides

Reaction of the dilithio derivative of phenylselenoacetic acid with epoxides leads to γ-substituted-α-phenylseleno-γ-butyrolactones, which upon oxidation–elimination, afford γ-substituted α,β-unsaturated γ-butyrolactones in high overall yield.