ORGANIC CHEMISTRYC H E M - 2 0 1
HYPERCONJUGATION
Lesson 6Dr. Erum A. HussainAssociate Professor
Department of ChemistryLCWU
Hyperconjugation Effect
The delocalization of σ-electrons or lone pair of electrons
into adjacent π-orbital or p-orbital is called hyperconjugation.
It occurs due to overlapping of σ-bonding orbital or the
orbital containing a lone pair with adjacent π-orbital or p-orbital.
It is also known as "no bond resonance" or "Baker-Nathan
effect".
There must be an α-CH group or a lone pair on atom
adjacent to sp2 hybrid carbon or other atoms like nitrogen,
oxygen.
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NO BOND RESONANCE
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Orbital diagram
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Stabi l i ty order of Carbocat ions
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Stabi l i ty order of a lkyl radica ls
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HYPERCONJUGATION IN ISOPROPYL CATION
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Hyperconjugat ion in Toluene
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Lets do it ! !
Ionization of Bromoethane
Propene cation
Benzyl radical
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