Which of the following carbocation is not resonance stabilised?

Question

Which of the following carbocation is not resonance stabilised? (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

In option d, there is SIR (Steric Inhibition to Resonance) The 2 methyl groups placed at ortho positions repel the carbocationic group thus mal-aligning the p- orbitals <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/chemistry/4e136acf092587b39ead5489c8d60ac7-.png" /> in the same plane, the π - electron cloud cannot enter the VACANT p- orbital from the ring.

Q. Which of the following carbocation is not resonance stabilised?

In option $d,$ there is SIR (Steric Inhibition to Resonance) The $2$ methyl groups placed at ortho positions repel the carbocationic group thus mal-aligning the $p -$ orbitals

in the same plane, the $π$ - electron cloud cannot enter the $V A C A NT p -$ orbital from the ring.

Q. Which of the following carbocation is not resonance stabilised?

In option d, there is SIR (Steric Inhibition to Resonance) The 2 methyl groups placed at ortho positions repel the carbocationic group thus mal-aligning the p− orbitals in the same plane, the π - electron cloud cannot enter the VACANTp−orbital from the ring.

In option $d,$ there is SIR (Steric Inhibition to Resonance) The $2$ methyl groups placed at ortho positions repel the carbocationic group thus mal-aligning the $p -$ orbitals

in the same plane, the $π$ - electron cloud cannot enter the $V A C A NT p -$ orbital from the ring.