The Effect of Conjugation

Vinyl and aryl groups that can conjugate to the cation can provide a significant amount of stabilization as seen in the relative rates of ionization (Table 5.3 in Carey & Sundberg).  A graphical depiction of this can be drawn from comparing electrostatic potential maps (identically indexed) for the benzyl cation, right, and the cyclohexylmethyl cation, left.  Note how the cyclohexylmethyl cation twists to gain hyperconjugative stabilization from the C-C bonds:

The decreased localization of charge in the benzyl cation is seen by the spread through the aromatic ring.

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Last updated: 09/21/00
Comments to K. Gable