Question

The most likely protonation site in the following molecule is:

• A. $C-1$
• B. $C-2$
• C. $C-3$
• D. $C-6$

Answer 1

The correct option is A $C-1$

Addition of a proton at $C^1$ results in the formation of tropylium carbocation (an aromatic species with more stability due to delocalisation of $\pi$ electrons), thus, it is the most reactive site towards protonation.

Addition of proton at any other carbon atom interrupt in the delocalisation of $\pi$ electrons. The disturbing planarity of molecules and hence makes it less stable. Thus, these all are less reactive towards protonation.