Hyperconjugative Interactions of the Carbon–Halogen Bond that Influence the Geometry of Cyclic α‑Haloacetals

The
analysis of the structures of low-energy conformers of different
α-haloacetals reveals changes in bond lengths and geometries
that correspond to stabilizing orbital interactions that contribute
to the ground-state structures of these systems. Several factors,
including the electron-donating and electron-accepting abilities of
the substituents on the ring, affect the degree of the electronic
interactions in these carbohydrate-like systems. The presence of an
α-halogen atom that can participate in hyperconjugation has
been shown to contribute to the structural characteristics of the
low-energy conformer. The experimental evidence is supported by natural
bond order (NBO) analysis to identify the types of interactions and
to assess their relative importance.