PtI ₄-catlyzed C-H bond functionalization in alkynyl ether: Density functional theory survey

In this article, the PtI ₄-catalyzed reaction mechanism for C-H bond functionalization in alkynyl ether is investigated using DFT methods. Two possible reaction pathways are explored in this reaction. Path 1 is associated with the direct [1,5]-hydride transfer, followed by the C-C bond formation, leading to cycloisomerization; path 2 corresponds to the [1,6]-hydride transfer after the formation of a Pt-vinylidene intermediate. Our results reveal that in both paths 1 and 2 the rate-determining processes are associated with the combination of C-C bond formation and [1,2]-hydrogen transfer toward the final product. We have also found that the existence of zwitterionic intermediates in solvent is very important. Due to the high irreversibility of zwitterionic intermediates, the selectivity of the reaction pathways should be controlled by the competition between [1,5]- and [1,6]-hydride transfer. Accordingly, it is found that path 1 is more favorable than path 2. Additionally, the acetonitrile solvent has a strong effect on the structures and energies during the reaction.