Transition Metal Catalyzed [π2s + π2s + σ2s + σ2s] Pericyclic Reaction: Woodward–Hoffmann Rules, Aromaticity, and Electron Flow
Alexander Q. Cusumano, William A. Goddard III, Brian M. Stoltz
Abstract
We have shown that the fundamental step responsible for enantioinduction in the inner-sphere asymmetric Tsuji allylic alkylation is C–C bond formation through a seven-membered pericyclic transition state. We employ an extensive series of quantum mechanics (QM) calculations to delineate how the electronic structure of the Pd-catalyzed C–C bond forming process controls the reaction. Phase inversion introduced by d orbitals renders the Pd-catalyzed [π2s + π2s + σ2s + σ2s] reaction symmetry-allowed in the ground state, proceeding through a transition state with Craig–Möbius-like σ-aromaticity. Lastly, we connect QM to fundamental valence bonding concepts by deriving an ab initio "arrow-pushing" mechanism that describes the flow of electron density through the reaction.
Group Members
Cusumano, A. Q., III, W. A. G., & Stoltz, B. M. (2020). Transition Metal Catalyzed [π2s + π2s + σ2s + σ2s] Pericyclic Reaction: Woodward–Hoffmann Rules, Aromaticity, and Electron Flow. *J. Am. Chem. Soc.*, *142*(45), 19033-19039. https://doi.org/10.1021/jacs.0c09575