The order of stability of the following carbocations:
is :
Stability of carbocation
III > I > II
Carbocation stability is determined by three main factors: hyperconjugation, resonance stabilization, and inductive effects. Tertiary carbocations are more stable than secondary, which are more stable than primary due to increased hyperconjugation and electron-donating effects.
Carbocation I: Secondary carbocation with no resonance stabilization
Carbocation II: Secondary carbocation stabilized by resonance with benzene ring (benzylic position)
Carbocation III: Tertiary carbocation with no additional resonance stabilization
Benzylic carbocations (II) have exceptional stability due to resonance delocalization into the aromatic ring:
II (benzylic secondary) > III (tertiary) > I (secondary)
Benzylic stabilization provides more stability than tertiary classification alone.
II > III > I
Stability Order: Benzylic > Tertiary > Secondary > Primary > Methyl
Hyperconjugation: More alkyl groups → more hyperconjugation → greater stability
Resonance Energy: Benzene ring provides approximately 36 kcal/mol resonance stabilization
The order of stability of the following carbocations:
is :
The product of the reaction given below is:
The major product of the following reaction sequence is
