Which of the following carbanions is the most stable?

A $(CH X_{3}) X_{3} C X^{-}$
B $CH X_{3} - CH X_{2} X^{-}$
C $(CH X_{3}) X_{2} CH X^{-}$
D $CH X_{2} = CH - CH X_{2} X^{-}$

Answer: D

The allyl anion delocalises the negative charge over two carbon atoms through resonance. Among simple alkyl carbanions, +I groups intensify the negative charge, so stability falls from ethyl to isopropyl to tert-butyl. Resonance is the strongest effect here, so allyl is most stable.

Practice General Organic Chemistry I: Electronic Effects More on Stability of resonating structures and conjugated species

Previous questionNext question

Which of the following carbanions is the most stable?

Answer: D

More questions on Stability of resonating structures and conjugated species