Investigating Cavity Quantum Electrodynamics-Enabled Endo/Exo-Selectivities in a Diels–Alder Reaction

Coupling molecules to a quantized radiation field inside an optical cavity has shown great promise in modifying chemical reactivity. Using the parametrized quantum electrodynamic (pQED) <i>ab initio</i> polariton chemistry approach, we theoretically demonstrate that the ground state selectivity of a Diels-Alder (DA) reaction can be fundamentally changed by strongly coupling this reaction to the cavity, generating preferential Endo or Exo isomers which are formed with equal probability for the same reaction outside the cavity. The numerical performance of pQED is in good agreement with the high-level self-consistent QED coupled cluster approach due to the exact light-matter interaction term used in pQED. By computing the ground state difference density, we show that the cavity induces a redistribution of electron density from intramolecular π-bonding orbitals to intermolecular bonding orbitals, providing chemical intuition of the cavity-induced changes to the ground state chemistry.