On the mechanism of rhodium-catalyzed [6+2] cycloaddition of 2-vinylcyclobutanones and alkenes

The intramolecular [6+2] cycloaddition mechanism of 2-vinylcyclobutanones and alkenes catalyzed by the [Rh(CO)2Cl]2 rhodium dimer has been studied using density functional theory, comparing this multi-step process with the one-step reaction in the absence of catalyst. According to our results the calculated mechanism agrees with what was previously experimentally suggested. Calculations have also allowed to explain the reaction selectivity.