14.2: Resonance and Allylic Carbocations
- Page ID
- 31033
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Conjugation occurs when p orbital on three or more adjacent atoms can overlap Conjugation tends to stabilize molecules. Allylic carbocations are a common conjugated system.
The positive charge of a carbocation is contained in a P orbital of a sp2 hybrizied carbon. This allows for overlap with double bonds. The positive charge is more stable because it is spread over 2 carbons.
The true structure of the conjugated allyl carbocation is a hybrid of of the two resonance structure so the positive charge is delocalized over the two terminal carbons. This delocalization stablizes the allyl carbocation making it more stable than a normal primary carbocation.
Relative Stabilities of Carbocations
Contributors
Prof. Steven Farmer (Sonoma State University)
Jim Clark (Chemguide.co.uk)
- Jeffrey Hu
