Stiles’ reagent ketone carboxylation

A carbonic acid derivative which, surprisingly, also proves to be suitable for the acylation of ketone enolates, is Stiles reagent, i.e., (methoxymagnesium) monomethyl carbonate. In Section 8.2, you saw how this reagent can be obtained. Ketone enolates are carboxylatedby Stiles reagent to furnish a /3-keto carboxylic acid, as shown by the reaction equation below. As this keto acid is initially obtained as the (methoxymagnesium) carboxylate, such an acylation can easily proceed without the extra equivalents of enolate or base mentioned above. 

Stiles extended use of the reagent to the tt-carboxylation of ketones to give /I-keto Hclds (3). The Inlermedlute mugneiium lilt (2) uen be ulkviuted In gliu... 

---