N-oxide-promoted intermolecularPauson–Khandreaction (PKR) has been studied. The addition of 15% ethylene glycol to the reaction mixture consistently increased (from 20% up to 2–4-fold) the reaction yields. The use of ethylene glycol as additive in the N-oxide-promoted intermolecularPauson–Khandreaction (PKR) has been studied. The addition of 15% ethylene glycol to the reaction mixture consistently