Revisiting the conformational analysis of unsaturated organic compounds using the bent bond / antiperiplanar hypothesis

Abstract

The bent bond/antiperiplanar hypothesis (BBAH) offers a straightforward qualitative model for interpreting the conformational analysis of simple unsaturated acyclic systems, as well as cyclohexene and methylenecyclohexane derivatives. The torsional profiles of a series of unsaturated compounds were computed by MP2 calculations, and their relative conformational outcomes were interpreted using the BBAH model. • Bent Bond (τ)/Antiperiplanar Hypothesis (BBAH) rationalizing the conformation of unsaturated molecules. • Conformation of simple unsaturated (allylic) acyclic molecules and τ bonds. • Conformation of cyclohexene and methylenecyclohexane molecules and τ bonds. • Torsional profiles of a series of unsaturated compounds computed by MP2 calculation and τ bonds. • Hydrogen Hyperconjugation Effect (HHE: σ.→ τ∗) and Generalized Anomeric Effect (GAE: τ CC → σ∗ CX ) and τ bonds