Question

Question #9f613

Answer 1

Several factors are involved.

Explanation:

The second resonance structure is more stable, because the negative is on the more electronegative oxygen atom.

However, we get methylation on the first structure because of other factors.

Here is a simplified explanation.

`"S"_text(N)2` reactions with `"CH"_3"X"` are essentially irreversible. Hence, the reactions are under kinetic control (You get the product that is formed most rapidly).

1. The `"O"` atom is a weaker nucleophile.

Because of its higher charge density, the `"O"` atom is strongly coordinated with `"M"^"+"` cations from `"MB"`.

This coordination sphere reduces the nucleophilicity of the `"O"` atom.

2 The `"C"`-methyl product is more stable than the `"O"`-methyl product, because a `"C=O"` bond is more stable than a `"C=C"` bond.

Hence the `"C"`-methylation pathway has a lower activation energy.

The above factors predict that 2-methylcyclohexanone will be the major product.