Metal–Ligand Cooperativity in Titanium-Catalyzed Anti-Markovnikov Hydroamination

Density functional theory (DFT) calculations were performed to investigate a known diamido bis­(amidate) Ti precatalyst that is excellent for anti-Markovnikov selective alkyne hydroamination. The coordination environments provided by the hemilabile amidate ligands were studied to reveal their spatial and electronic influence on the structures and energies of intermediates and transition states. Several factors contribute to the unique regioselectivity of this catalytic system, including orbital interactions, ligand coordination modes, and steric repulsion. The turnover-limiting step was found to be substrate-dependent. Experimental evidence was obtained to further test computationally generated hypotheses. These investigations show that the bis­(amidate) Ti catalytic system’s high regioselective performance can be attributed to ligand hemilability, which promotes metal–ligand cooperativity in the reaction mechanism.