Aromatic rings represent a fundamental structural motif in chemistry, frequently found in a broad range of important compounds, including biomolecules, pharmaceuticals, polymers, dyes, and fragrances. Chemical bonds with aromatic character, present in these structures, show a distinct behaviour in comparison to typical double bonds. Whereas the functionalization of aromatic compounds by substitution reactions is well-explored and widely utilized, the cleavage of inert aromatic carbon–carbon bonds remained challenging due to the unfavourable energetics of permanently rupturing aromaticity. One of the approaches to create and break double bonds is alkene metathesis – an exceptionally versatile reaction that has been broadly adopted across different sectors in the chemistry industry. In contrast to the significant progress achieved for alkene metathesis, aromatic compounds have been considered unsuitable substrates for this transformation. Given the broad abundance of (hetero)aromatics and the wide array of structurally appealing and otherwise inaccessible products obtained upon direct cleavage of aromatic rings, the development of methodologies enabling this goal is of significant interest. In our work, we observed the first examples of aromatic ring-opening metathesis, answering the longstanding question of whether aromatic systems can participate in this catalytic reaction. Furthermore, using a chiral molybdenum catalyst, the method allowed the enantioselective synthesis of molecules that are hindered in rotation, which are highly relevant for drug development and beyond.

Original publication
Valeriia Hutskalova, Christof Sparr
Aromatic ring-opening metathesis
Nature 638, 697–703 (2025). DOI: https://doi.org/10.1038/s41586-024-08472-z