Résumé : We have developed an efficient and general synthesis of ynimines based on an oxidative cross-coupling between imines and alkynylcopper reagents. Upon simple addition of 1,2-dimethylimidazole in the presence of oxygen, these bench-stable, crystalline and readily available polymeric compounds were found to be especially suitable reagents for the introduction of an alkynyl group onto a wide range of ketimines at room temperature and under especially mild conditions.