Metathesis reactions articles from across Nature Portfolio

Classical metalation reactions in organic synthesis typically involve metal-halogen exchange. Here, the authors introduce a metal-carbon exchange strategy that enables the skeletal editing of biologically relevant lactams by a Ni(0) compound.

Olefin metathesis is a powerful synthetic method that largely rests on the reactivity of molybdenum- and ruthenium-based catalysts, as alternative metals have not yet been successfully substituted. Here the authors engineer an iron catalyst to effectively perform the stereoselective ring-opening metathesis polymerization of norbornene.

Metathesis reactions involving carbon–carbon double bonds have been well established, but direct metathesis of carbon–carbon single bonds is extremely rare. Now, a ruthenium-catalysed carbon–carbon single-bond metathesis reaction has been developed with unstrained homo-biaryl substrates. The reaction shows wide functional group tolerance and operates via an ‘olefin-metathesis-like’ mechanism.

Air-sensitive molybdenum olefin metathesis catalysts are known to form stable but inactive adducts with appropriate chelating ligands, but regenerating the active catalyst requires the use of Lewis acids and vigorous conditions. Here, tuning the electron donor capacity of the ligands leads to air-stable solid adducts of tungsten and molybdenum alkylidenes that spontaneously release the active catalysts in solution.

The metathesis of carbon–carbon double bonds is an important tool in organic synthesis and now a similar reshuffling has been carried out with heavier alkene analogues featuring unsymmetrically substituted Ge=Ge double bonds. This reaction enables the synthesis of symmetric molecular digermenes as well as a polymer based on Ge=Ge repeat units.

Biocompatibility plays a crucial role for the development of artificial metalloenzymes (ArMs) for therapeutic applications. This work presents an ArM with a ruthenium catalyst that is protected from physiological glutathione and accumulates in cancer cell lines for metathesis-mediated prodrug activation.

Carbon–carbon single bonds are generally among the least reactive chemical bonds. While olefin metathesis reactions are well established, direct metathesis of C–C single bonds is rare. Now, a C–C single bond metathesis reaction has been developed, forming cross-biaryl products from unstrained homo-biaryl compounds.

Carbonyls and alkenes, two of the most common functional groups in organic chemistry, generally do not react with one another. Now, a simple Lewis acid has been shown to catalyse metathesis between alkenes and ketones in a new carbonyl olefination reaction.

Metathesis reactions can be used to make carbon–carbon double bonds — bar one isomeric class. By using new catalysts and balancing out the stabilities of intermediates in the reaction, the elusive isomers can be made. See Article p.461

Olefin metathesis is a flexible and efficient method for making carbon–carbon bonds and has found widespread application in academia and industry. Now, a detailed mechanistic study looking at key catalytic intermediates offers new insight into this reaction, and may prove useful in the development of more active and selective catalysts.

A Brønsted acid co-catalyst is the key to the synthesis of furans by alkene cross-metathesis.