Navigating Past a Fork in the Road: Carbocation-π Interactions Can Manipulate Dynamic Behavior of Reactions Facing Post-Transition-State Bifurcations.

Dynamics calculations are described for carbocation rearrangements involving product-forming pathways with post-transition-state bifurcations. We show that noncovalent interactions with associated benzene rings (a simple model of aromatic amino acid side chains) can switch inherent dynamical tendencies for competing modes of disrotation, establishing that meaningful changes in dynamically controlled product selectivity can be achieved with few weak noncovalent interactions.