Theoretical insights into the selectivity of 1,6-enyne cycloisomerization on gold clusters: Orbital interaction role

Abstract

In the present article, the mechanism of 1,6-enyne cycloisomerization catalyzed by the planar Au8 cluster was investigated in details by means of density functional theory. The effects of the size and shape of the gold nanoclusters (Au7-20) on their catalysis of 1,6-enyne cycloisomerization were also studied. The computational results indicate that the main reaction channels of the 1,6-enyne cycloisomerization on the Au8 cluster are the 5–exo–anti–cycloisomerization, and the single cleavage pathway is slightly more feasible than the double cleavage pathway. The selectivity of 1,6-enyne cycloisomerization catalyzed by the gold clusters is controlled by the orbital interaction between the gold atoms and the carbene fragment in the migration of CH2 group. In addition, the influence of coordinate environment of the gold atoms on adsorption energy, catalytic activity, and regio-selectivity were amply interpreted as well.