Fundamentals of Organic ChemistryChemistryGeneral Organic Chemistry
Which of the following best describes the phenomenon of hyperconjugation?
Options
- ADelocalisation of electrons into a nearby empty orbital
- BDelocalisation of p electrons into a nearby empty orbital
- CThe effect of alkyl groups donating a small amount of electron density inductively into a carbocation
- DThe migration of a carbon or hydrogen from one carbocation to another
Correct answer
A. Delocalisation of electrons into a nearby empty orbital
Step-by-step solution
Hyperconjugation involves the delocalisation of electrons (typically from a C-H or C-C bond) into an adjacent empty or partially filled p-orbital or -orbital. This interaction helps to stabilize the molecule or reactive intermediate, such as a carbocation or free radical. Option (B) describes resonance or -conjugation. Option (C) describes the inductive effect. Option (D) describes carbocation rearrangement (such as hydride or alkyl shifts). Answer: Delocalisation of electrons into a nearby empty orbital