Cleaving arene rings for acyclic alkenylnitrile synthesis

Synthetic chemistry is built around the formation of carbon–carbon bonds. However, the development of methods for selective carbon–carbon bond cleavage is a largely unmet challenge1–6. Such methods will have promising applications in synthesis, coal liquefaction, petroleum cracking, polymer degradation and biomass conversion. For example, aromatic rings are ubiquitous skeletal features in inert chemical feedstocks, but are inert to many reaction conditions owing to their aromaticity and low polarity. Over the past century, only a few methods under harsh conditions have achieved direct arene-ring modifications involving the cleavage of inert aromatic carbon–carbon bonds7,8, and arene-ring-cleavage reactions using stoichiometric transition-metal complexes or enzymes in bacteria are still limited9–11. Here we report a copper-catalysed selective arene-ring-opening reaction strategy. Our aerobic oxidative copper catalyst converts anilines, arylboronic acids, aryl azides, aryl halides, aryl triflates, aryl trimethylsiloxanes, aryl hydroxamic acids and aryl diazonium salts into alkenyl nitriles through selective carbon–carbon bond cleavage of arene rings. This chemistry was applied to the modification of polycyclic aromatics and the preparation of industrially important hexamethylenediamine and adipic acid derivatives. Several examples of the late-stage modification of complex molecules and fused ring compounds further support the potential broad utility of this methodology. Common aromatic rings, such as anilines, arylboronic acids and aryl halides, can be opened up and converted to alkenyl nitriles through carbon–carbon bond cleavage using a copper catalyst.