α‐Alkylene‐β‐lactone is an important skeleton in a variety of biologically active molecules. It is of great significance to study the mechanism of regioselective cyclocarbonylation of tertiary alkynols catalyzed by palladium, which is applied to the synthesis of α‐alkylene‐β‐lactone. We employed density functional theory (DFT) calculations at the M06‐2X level to investigate the valence state of Pd participating in the catalytic cycle, the reaction pathways, and the mechanism of ligand‐controlled regioselectivity. Our results reveal that palladium participates in the reaction with the Pd(II) oxidation state. Distortion/interaction–activation strain(D/I‐AS) analyses indicate that the regioselectivity of the reaction with ligand L1 is predominantly governed by hydrogen–bond interaction in alkyne migration insertion, while the regioselectivity of the reaction with ligand L2 is mainly governed by kinetically suppressing byproduct formation.
Xie et al. (Tue,) studied this question.