[MonkeyDust]

can pivaloyl chloride (trimethylacetyl chloride) produce a t-butyl cation, in the presence of AlCl3 ??

[Squirmy]

Yes, this happens to some extent, giving mixtures of acylated and alkylated material.

Can you show a mechanism for formation of the t-butyl cation?

[MonkeyDust]

well i thought that AlCl3 could coordinate to the oxygen and any free Cl- could attack the carbonyl to give a tetrahedral centre and then the bond between the carbonyl carbon and the alpha carbon could undergo heterolytic fission to give a t-butyl cation and a stabilised carbanion, but this sounds far-fetched.

[Squirmy]

A hint: one of the byproducts is a gas.

[MonkeyDust]

carbon monoxide? AlCl3 removes Cl- to give acylium, lose CO to give cation?

[Squirmy]

That sounds a lot better.

[MonkeyDust]

cheers