Ab initio and DFT calculations have been carried out to study the reaction mechanism between diformylketene and formamide. Gas-phase calculations show that the mechanism is concerted in contrast to the results of a previous paper. However, although it appears there is one single transition state, the characteristics of its structure reveal a very asynchronous reaction mechanism. The reaction is clearly exothermic and as well has a rather small activation energy. Its pseudopericyclic character has been confirmed by calculation of magnetic properties. The effect of solvent has been analyzed by using the Onsager and PCM methods: substantial changes have not been found in solution.