Multimetallic systems are expanding the frontiers of modern organometallic catalysis toward new synthetic challenges. The synergistic activation of distinct co-substrates, or functionalities avoids harsh conditions, the use activating agents or pre-functionalization strategies accounting for safe chemistry, waste reduction and atom economy principles. However, a complete control of the synergy between the catalytic partners is far from be reached. Their intimate mechanism, redox compatibility and competition between catalytic cycles is still an open question. Computational chemistry, particularly density Functional Theory (DFT) recently emerged as a valuable option able to clarify both mechanism and driving factors of cooperative processes. However, due to the large dimension and conformational complexity of these multicomponent systems, deep mechanistic studies are still scarce.<br/><br/>In this presentation, we report our DFT study on the mechanism and molecular factors driving the mild Ni0(binap)/CuI(phospherrox) cooperative asymmetric propargylic alkylation of aldimine esters recently reported experimentally by Guo and co-workers. The real system was fully explored accounting for conformational changes and aggregation processes. Activation strain model and Non Covalent Interaction (NCI) analysis deciphered the origin of the selectivity. Both catalysts act independently toward the activation of the substrates, while the selectivity takes place during the cooperative C-C coupling driven by intercatalyst pi−pi and CH−pi non-covalent interactions.

DFT study on the mechanism of a Ni/Cu cooperative asymmetric propargylation

ACS Spring 2022

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