Theoretical investigation on the selectivity in the palladium-catalyzed reaction of oxidative carbonylation-carbocyclization-carbonylation-alkynylation of enallene

The mechanistic study of palladium-catalyzed reaction of oxidative carbonylation-carbocyclization-carbonylation-alkynylation of enallene was carried out by using density functional theory (DFT). Our calculated results indicate that P1 is the only product and other side products could not be obtained in the experiment. The instability of P2 is caused by the strong ring strain. Without the coordination of CO, P3 and P4 are calculated to be inaccessible. P1 is preferred over P5 can be attributed to the electronic effect by performing NBO analysis. The present calculated study elucidates the experimental observation at the molecular level.