Large Hyperconjugation in Strained Systems

Julien Racine (1) , Stéphane Humbel (1)

1 ISM2 - Institut des Sciences Moléculaires de Marseille

Carbocations can appear as transient species, for instance, in elimination reactions and various rearrangements. Hyperconjugation (or conjugation) can then stabilize the cationic character and form a partial π bond. The effect of the electronic delocalization from strained substituents to a carbocation part was calculated. Very large hyperconjugation was found, sometimes more than 80 kcal mol-1, which is much larger than typical conjugation effects (56 kcal mol-1 for the allyl cation).

Keywords: carbocations; charge transfer; density functional calculations; hyperconjugation; strained molecules

Domains: Chemical Sciences; Theoretical and/or physical chemistry

Julien Racine, Stéphane Humbel. Large Hyperconjugation in Strained Systems. Chemistry - A European Journal, 2014, Chemistry a European Journal, 20, pp.12601-12606. ⟨10.1002/chem.201403582⟩. ⟨hal-01347475⟩