Comparing Stability of Allylic Carbanions

AI Thread Summary
The discussion centers on the stability of allylic carbanions formed from the cleavage of C-H bonds. It highlights that carbon's electronegativity leads to the formation of carbanions, with resonance playing a key role in their stability. Specifically, cleavage at position 'b' produces a more stable allylic carbanion compared to position 'a', which results in a vinylic carbanion. The participants clarify that positions 'b' and 'd' are relevant for producing allylic carbanions, with 'b' being the most stable. Overall, the resonance stabilization significantly influences the stability of the resulting carbanions.
gpavanb
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Homework Statement


Look at the diagram accompanying the question. Which has least C-H bond energy?


The Attempt at a Solution


On cleavage of a C-H bond, a carbanion is formed as carbon is more electronegative than hydrogen. So cleavage of (b) results in a carbanion stabilized by resonance
 

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gpavanb said:

Homework Statement


Look at the diagram accompanying the question. Which has least C-H bond energy?


The Attempt at a Solution


On cleavage of a C-H bond, a carbanion is formed as carbon is more electronegative than hydrogen. So cleavage of (b) results in a carbanion stabilized by resonance

You can form 2 allylic (stabilized by resonance) carbanions (a and b). Which one is most stable?
 
Cleavage of a results in a vinylic carbanion. b forms the more stable allylic carbanion
 
Sorry, I read that wrong. It should have been position 'b' and 'd' produce the allylic carbanions. Which one is most stable?
 

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