Revisited the reaction mechanism of cobalt catalyzed [3+2] cycloaddition reactions between the derivatives of cyclopropanols and allenes: A DFT study

A theoretical study on the cobalt catalysed [3+2] cycloaddition reaction between cyclopropanol and allene has been performed using DFT method. It reveals that a stepwise pathway is favourable which involves the sequence of cleavage of cyclopropanol derivatives and carban-carbon bond formation and finally generation of cyclopentane derivatives with exocyclic double bonds. Substituted reactants raise the possibility of diastereoselectivity in the cycloaddition reactions. The steric interaction by the variation of substituents decides the reaction to progress selectively in a specific direction leading to a specific diastereomeric product in high yield. The study explains the experimentally observed selectivity of products for the metal catalysed cycloaddition in generating cyclopentane structure.