A facile route to N-acetyl α,β-unsaturated γ-lactam derivatives using ethyl acetamidocyanoacetate and dialkyl acetylenedicarboxylate in the presence of triphenylphosphine

The three component reaction of ethyl acetamidocyanoacetate with dialkyl acetylenedicarboxylates and triphenylphosphine leads to phosphorus ylides in good yields. These ylides undergo a 1,2-proton shift, loss of triphenylphosphine, and subsequent intramolecular amidation leads to the formation of N-acetyl α,β-unsaturated γ-lactams.