CONTEXT

The formation of an aryl-aryl bond is one of the most important goals in the field of organic chemistry. Biaryls are core scaffolds of commercially very important structures often found in electroactive materials and in biologically active molecules such as anticancer agents.

Traditionally, these compounds have been prepared by metal-catalyst mediated coupling reactions (Suzuki, Stille, Negishi reactions…) or by nucleophilic aromatic substitution (S_NAr) involving constraining protection/deprotection steps (Meyers, Miyano reactions). Due to potentially toxic contamination of pharmaceutical products, effective removal of metals (Pd, Cu…) in active pharmaceutical ingredients (API) poses acute problems inasmuch as the limits set by health authorities are very low (see http://www.emea.europa.eu/pdfs/human/swp/444600en.pdf). S_NAr reactions have suffered from several limitations, the most severe being most certainly the difficulty of removal of the protecting group.