Hyperconjugation is a general stabilising interaction. It involves delocalisation of electrons of C–H bond of an alkyl group directly attached to an atom of unsaturated system or to an atom with an unshared p orbital.
The s electrons of C–H bond of the alkyl group enter into partial conjugation with the attached unsaturated system or with the unshared p orbital. Hyperconjugation is a permanent effect.
