Direct Transformation of Esters into Arenes with 1,5‐Bifunctional Organomagnesium Reagents

Abstract A direct transformation of carboxylic acid esters into arenes with 1,5‐bifunctional organomagnesium reagents is described. This efficient and practical method enables the one‐step defunctionalization of various carboxylic acid esters to prepare benzene, anthracene, tetracene, and pentacene derivatives. A double nucleophilic addition of the 1,5‐organodimagnesium reagent to the ester is followed by an immediate 1,4‐elimination reaction that leads to the direct [5+1] formation of a new aromatic ring.