Correlated shapeshifting and configurational isomerization.

Herein we demonstrate that the rapid 'shapeshifting' constitutional isomerization of a substituted bullvalene is influenced by the -to- configurational isomerization of a remote carbamate group, giving rise to correlated motion. We find that, while the -configurational isomer of a bulky carbamate favors the -bullvalene constitutional isomer, a noncovalent bonding interaction within the -carbamate tips the equilibrium toward the -bullvalene form. Using DFT modelling and NMR spectroscopy, this long-range interaction is identified as being between the bullvalene core and a pendant phenyl group connected to the carbamate.

A guide to bullvalene stereodynamics.

Here, we analyze the stereodynamic properties of bullvalenes using principal moments of inertia and exit vector plots to draw comparisons with commonly used ring systems in medicinal chemistry. To aid analyses, we first classify (i) the four elementary rearrangement steps available to substituted bullvalenes, which (ii) can be described by applying positional descriptors (α, β, γ, and δ) to the substituents. We also (iii) derive an intuitive equation to calculate the number of isomers for a given bullvalene system.