Alkyne-dicobalt hexacarbonyl complexes have been studied by DFT to examine
whether electronic differences in the acetylenic substituents could play a
role in determining the regiochemical outcome in the Pauson-Khand reaction.
It appears that in some instances the regiochemistry is, in fact, governed
exclusively by the electronic nature of the acetylenic substituents throug
h the discriminant loss of a carbon monoxide ligand.