LG

“An essential quality of a good research atmosphere is to be able to question any result or hypothesis… The best advice I have ever been given is to not take grant rejections personal…”

Find out more about Robert Luxenhofer in his Introducing… Profile.

In this scientific perspective, we intend to provide a coherent framework for the field of magnetocatalysis by highlighting opportunities associated with the use of magnetic fields to activate catalysts. A particular focus will be placed on magnetically induced catalysis , providing an overview on current advances and identifying scientific and technical challenges on the path toward a widespread use of this technology in research and industry.

Abstract

The rapidly growing importance of electrification in the chemical industry opens room for disruptive innovations regarding energy input into catalytic processes. Energy efficiency and dynamics of renewable energy supplies represent important challenges, but the design of catalytic systems to cope with such new frameworks may also stimulate the discovery of new catalyst materials and reaction pathways. In this context, many opportunities arise when catalysts are activated in a rapid, localized, and energy-efficient manner. Among the various concepts to achieve adaptivity in catalysis, magnetic induction heating applied directly at the catalyst or in vicinity of the active site has gained increasing attention recently. In this Scientific Perspective, we provide a coherent framework to the emerging field of catalysis using magnetic fields—and in particular alternating current magnetic fields—to activate catalytic materials and define it as magnetically induced catalysis . Promising approaches and selected examples are described to illustrate the scientific concept and to highlight its broad potential for innovation in catalysis from laboratory to industrial scale.

Nature Chemistry, Published online: 20 March 2025; doi:10.1038/s41557-025-01772-5

Chemical energy conversion and storage rely on the selective movement of protons and electrons, thus understanding these processes is important for applications. Now experiments at elevated pressures are shown to identify excited-state proton-coupled electron transfer mechanisms and to facilitate merging proton transfer with subsequent electron transfer steps towards a concerted pathway.

Ultrafast absorption spectroscopy highlights that the excited state of the radical anion of 4DPAPN, a TADF chromophore employed as a photocatalyst, is not directly involved in a ConPeT mechanism. Instead, its high reducing ability stems from the generation of solvated electrons through a two-photon process in acetonitrile solution.

Abstract

Recently, in a communication to this journal, Qiao, Jang, and coworkers described an asymmetric photoredox reaction promoted by TADF cyanoarene photocatalysts (specifically 4DPAPN (3,4,5,6-tetrakis(diphenylamino)phthalonitrile)). The authors claimed that the high reduction potential required for the reaction in acetonitrile was achieved by the radical anion of the photocatalyst in its excited state, which initiated the reaction. This mechanism is usually named consecutive photoinduced electron transfer (ConPeT), in which two photons are involved: the first one to excite the photocatalyst and generate the radical anion 4DPAPN ^•– and the second photon to promote 4DPAPN ^•– to its excited state *4DPAPN ^•–. Employing ultrafast transient absorption spectroscopy, here we report that, although two photons are indeed involved in this transformation, the excited state *4DPAPN ^•– is short-lived, not emissive, and not quenched by the organic substrate employed in the reaction, opposite to what was claimed by the authors. The photocatalyst in the excited state *4DPAPN ^•– can generate a solvated electron that is able to reduce the substrate involved in this chemistry. It is worth noting that a different photochemical mechanism is likely to be operative in CH₂Cl₂, where solvated electrons are much less stabilized and reduction of the solvent might occur.

Nature Chemistry, Published online: 11 March 2025; doi:10.1038/s41557-024-01729-0

Transfer hydrogenation is challenging to apply to aryl halide reductive cross-couplings because of competing hydrogenolysis. Now aryl halide cross-couplings mediated by sodium formate have been developed. These processes display orthogonality to Suzuki and Buchwald–Hartwig couplings as pinacol boronates and anilines are tolerated and, owing to chelated intermediates, effective for challenging 2-pyridyl systems.

Electrochemical amino-oxygenation of alkene radical cations with bisnucleophiles enabled the formation of saturated N/O-heterocycles. In situ EC-MS data offered valuable insights into the radical cation-initiated difunctionalization, allowing precise control over regio- and chemoselectivity.

Abstract

Regioselective functionalization of alkenes to create nitrogen- and oxygen-containing heterocycles remains a significant challenge in organic synthesis. Because of their unique electronic and biological properties, these heterocycles are crucial in pharmaceuticals and materials. Herein, we present an electrochemical amino-oxygenation of alkenes using alkene radical cations and bisnucleophiles, enabling the synthesis of saturated N/O-heterocycles in an undivided cell. This method employs readily available amides and alkenes, eliminating the need for additional oxidants or redox catalysts. The in situ generation of alkene radical cations results in high yields with excellent regio- and chemoselectivity. Our approach offers a direct route to six-, seven-, and eight-membered N/O-heterocycles from simple starting materials, broadening access to complex molecules essential for medicinal chemistry and materials science.

Direct coupling of free alcohols with electron-rich alkenes—a longstanding challenge due to inherent polarity mismatches—is achieved via a ligand-to-metal charge transfer (LMCT)-enabled catalytic platform featuring cerium(IV) benzoate catalysts. This anti-Markovnikov hydroetherification proceeds through selective activation of free alcohols into alkoxy radicals, facilitated by LMCT homolysis, even in the presence of redox-labile electron-rich alkenes such as enol ethers. Mechanistic studies elucidate the structure of the active Ce(IV) benzoate complex, highlighting its unique selectivity for alkoxy radical generation.

Abstract

We present a ligand-to-metal charge transfer (LMCT)-enabled catalytic platform utilizing cerium(IV) benzoate complexes to address the long-standing challenge of directly coupling free alcohols with electron-rich alkenes, overcoming inherent polarity mismatches. This approach effectively circumvents the typical selectivity in single-electron transfer processes, enabling the selective generation of electrophilic alkoxy radicals from free alcohols in the presence of redox-labile electron-rich alkenes. The Ce-benzoate-based photocatalytic protocol promotes regioselective hydroetherification via both intramolecular cyclization and intermolecular addition pathways, showcasing broad functional group tolerance, operational simplicity, and versatility across a diverse array of alkenes, including silyl enol ethers and enamides/enecarbamates. Detailed mechanistic studies elucidate the structure of the active Ce(IV) benzoate catalyst, highlighting its unique selectivity for alkoxy radical generation, thereby establishing a practical and atom-economical framework for hydroetherification.

The first general palladium/norbornene (Pd/NBE) catalysis with aryl chlorides is achieved by employing a secondary-amide-substituted NBE and XPhos ligand, resulting in diverse ortho/ipso difunctionalizations of arenes.

Abstract

While the palladium/norbornene (Pd/NBE) cooperative catalysis has become increasingly useful for arene functionalization, its substrate scope has been mainly restricted to reactive aryl iodides and bromides. Despite being a more available and attractive feedstock, common aryl chlorides have not been used as substrates for the Pd/NBE catalysis. Herein, we report the first general Pd/NBE-catalyzed vicinal difunctionalization of aryl chlorides. Enabled by the combination of secondary-amide-substituted NBEs and XPhos ligand, diverse aryl chlorides can now undergo successful ortho alkylation, amination, and acylation with different ipso terminations, including olefination, hydrogenation, and alkynylation. To show the utility of this method, late-stage derivatizations of complex bioactive compounds and sequential functionalizations of polyhaloarenes have been achieved.

The decarboxylative ring-opening functionalization of strained and non-strained cyclic tertiary acids (3–12-membered rings) under Ce/photocatalysis, with air as the sole oxidant, is reported. This strategy enables the construction of C─CN, carbon–halide, C─C, C─Se, and carbon─oxime bonds to form various functionalized carbonyl compounds. Late-stage modifications generate valuable molecular modules, providing a pathway for antipsychotic drug synthesis.

Abstract

The selective cleavage of inert carbon-carbon bonds in unstrained rings continues to pose a formidable challenge in chemical synthesis. Current methods for C(sp³) ─C(sp³) bond cleavage are highly limited, typically relying on transition-metal catalysis to facilitate ring-opening via small-ring strain or inducing β-fragmentation after generating radicals from oxygen or nitrogen atoms pre-installed in the substrate. Herein, we introduce an effective strategy for the decarboxylative ring-opening functionalization of α-trisubstituted carboxylic acids, mediated by both light and cerium. This method enables the ring-opening of carboxylic acids with ring sizes ranging from 3 to 12 members, allowing the construction of C─CN, C-halide, C─C, C─Se, and C─oxime bonds. Notably, this reaction does not require the pre-installation of an oxygen atom in the substrate, as the carbonyl group is derived from atmospheric oxygen. Furthermore, late-stage modification establishes distally functionalized carbonyl compounds, which serve as versatile synthons for accessing valuable building blocks.