The ability to predict the reactivity and selectivity of transition metal catalysts will revolutionize reaction discovery and optimization processes. Achieving this goal requires close collaboration between experimental and computational chemists to ensure that predicted mechanisms, transition states, and reaction products are accurate. In this presentation, we show through experiment-guided theory that incorporating experimental parameters for temperature, and CO concentration into the DFT calculations were required for accurate identification of the two possible catalytic pathways involving either a four- or five-coordinated Rh species. Taking experimental conditions into account is critical for predicting the major enantiomer of the Pauson–Khand reaction (PKR) product because the two competing mechanisms lead to opposite enantioselectivities. Through theory-guided experiment, we show that the Rh(I)-catalyzed enyne PKR with a bidentate phosphine ligand and a monodentate phosphoramidite ligand both prefer a mechanism involving the four-coordinate oxidative addition, rather than the five-coordinate oxidative addition previously established in our work with the PKR of allenes. Through these studies, we aim to extend the scope of the asymmetric Rh(I)-catalyzed PKR and gain a better understanding of transition-metal catalyzed asymmetric multicomponent cycloaddition reactions.

Mechanism and origins of enantioselectivity in the Rh(I)-catalyzed pauson: khand reaction

ACS Spring Meeting 2021

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