Enrico

Electrocatalytic hydrogenation (ECH) of furfural under acidic conditions is examined using Pd/C and Pd-TiON_x/GO catalysts. Differences in redox behavior and adsorption properties are observed. Pd/C exhibits higher selectivity toward furfuryl alcohol, while Pd-TiON_x/GO favors 2-methylfuran formation. Metal–support interactions and surface properties are shown to play a key role in tuning ECH activity and selectivity.

Electrocatalytic hydrogenation (ECH) offers a sustainable alternative to conventional hydrogenation of biomass-derived compounds by using cathodic potential instead of heat and molecular hydrogen. This study explores the ECH of furfural under acidic conditions, focusing on how metal–support interactions influence the performance of Pd-based catalysts. Two systems are compared: Pd on carbon (Pd/C) and Pd supported on titanium oxynitride-graphene oxide (Pd–TiONx/GO). Pd–TiONx/GO exhibits lower oxophilicity and a higher proton adsorption tendency than Pd/C. Additionally, its surface shows a more negative charge, indicated by a cathodic shift (≈10 mV) in the potential of zero total charge measured via N₂O reduction. These differences significantly affect catalytic behavior. While Pd/C shows roughly twice the activity for converting furfural to furfuryl alcohol (FA), Pd–TiONx/GO is over 100 times more active in producing 2-methylfuran (2-MF) and also enhances the competitive hydrogen evolution reaction. This suggests Pd–TiONx/GO has lower surface coverage by furfural and FA, allowing for more hydrogen adsorption and favouring 2-MF formation. Overall, the study demonstrates that Pd's electrosorptive and catalytic properties can be tuned via electronic effects from the TiONx support, enabling selective manipulation of ECH pathways.

The Cover Feature highlights the broad potential of nitrogen-functionalized lignin across sustainable technologies, including energy, environmental remediation, agriculture, catalysis, and biomedicine. The illustration incorporates symbolic elements—batteries, water treatment, plants, and apoptotic cells—representing versatile applications. A nitrogen atom is depicted as a functional bridge, enhancing lignin’s reactivity and functionality. Together, these elements underscore lignin’s promise as a green, adaptable platform for future innovations. More information can be found in the Review by H. Du, X. Pan and co-workers (DOI: 10.1002/cssc.202500607).

ChemSusChem, Volume 18, Issue 17, September 1, 2025.

Nature Synthesis, Published online: 28 July 2025; doi:10.1038/s44160-025-00856-x

Pyrroles to pyridines

Spontaneous and ultrafast C─O/C─C bond cleavage of various lignin models was achieved by taking advantage of the unique and strong alkaline environment at the air–water interface of a negatively charged water microdroplet, yielding value-added aromatic chemicals.

Abstract

Bulk water serves as an inert environment for lignin linkages, resulting in their natural half-lives that extend over centuries. In this study, we present the striking results of the spontaneous and ultrafast C─O/C─C bond cleavage of various lignin models in water microdroplets, yielding value-added aromatic chemicals. The β-O-4 linkages, the most abundant interunit linkages in natural lignin, were selectively cleaved at C_β─O bonds, producing phenols in yields exceeding 70%. Mechanistic studies elucidated that the cleavage of β-O-4 linkages is derived from the unique alkaline environment at the air–water interface of a negatively charged water microdroplet, even in the absence of extra alkalis. The challenging cleavage of the highly stable C_α─C_β bonds in β-O-4 and β-1 lignin linkages was also accomplished, yielding valuable benzoic acid product. Mechanistic investigations revealed that the oxidation of the substrates by molecular oxygen is the key step for the C_α─C_β bond cleavage. Notably, all intermediates, including the fragile peroxide intermediates, were identified using mass spectrometry. Accompanied by evidence from radical scavenging and ¹⁸O labeling, the mechanisms for the selective C─O/C─C bond cleavages have been unambiguously characterized, paving a new and green way for the cleavage of lignin linkages.

We report a multicomponent reaction involving an aryl halide, an aldehyde, and a silane derivative, facilitated by low-valent bismuth redox catalysis under mild conditions. The protocol represents an unprecedented example of four elementary organometallic steps at a Bi center within the catalytic cycle. Experimental and computational studies indicate the involvement of intermediate species that supports a Bi(I)/Bi(III) cycle.

Abstract

Herein, we report a catalytic defluorinative arylation of aldehydes with (per) A fluoroarenes facilitated by a pincer-based PheBox-Bi(I) under mild conditions. The protocol features various novel aspects in bismuth redox catalysis; namely, (1) a catalytic 1,2-aryl migratory insertion to forge a C─C bond, (2) an unprecedented example of multicomponent reaction through four elementary organometallic steps at a Bi center, (3) an unusual strategy for Bi(I) compounds regeneration via O─Si reductive elimination. Experimental and computational studies aided in dissecting the various mechanistic aspects of the bismuth redox cycle.

The α,α-difluoromethylene amine (NCF2R) motif represents a useful functionality in medicinal chemistry, yet practical and modular methods to access this class of compounds are lacking. Here, we report a safe and scalable flow-based strategy for the on-demand generation of NCF2R anions using a packed-bed microreactor containing caesium fluoride. This protocol enables the late-stage installation of the CF2 group under mild conditions, avoiding the use of hazardous fluorinating agents and minimizing fluorinated waste. This fully modular strategy features three points of diversification (carboxylic acid, sulfonamide, and electrophile), allowing efficient access to a broad range of α,α-difluoromethylene amines. The method tolerates a variety of functional groups, supports late-stage functionalization of pharmaceutically relevant scaffolds, and is compatible with downstream cross-coupling reactions, demonstrating the robustness of the reaction protocol. This work provides a versatile platform for the streamlined incorporation of NCF2 motifs, expanding the range of synthetic strategies available in medicinal and fluorine chemistry.

The intensification of electrochemical hydrocarboxylation reaction employing a spinning cylinder electrode reactor is presented. The optimized system provides high reaction scale for the synthesis of valuable compounds, incorporating CO₂ gas in organic molecules in an efficient way.

There is an increasing attention in developing reactions that can incorporate CO₂ into organic molecules. In this context, electrochemistry offers a sustainable and mild approach to utilize this valuable yet elusive C1 building block in a scalable fashion. Herein, the intensification of the electrochemical hydrocarboxylation of activated alkenes is presented. The study covers the evaluation of critical chemical and electrochemical parameters to maximize the efficiency of the process in standardized small-scale batch cells, followed by the transfer to a spinning cylinder electrochemical reactor. Leveraging the enhanced mass transfer of this reactor design, the reaction can be further optimized, leading to a more efficient process. After validating the transformation across different substrates, the regioselective addition of CO₂ is further improved by tuning the current density of the process. Finally, a scale-up in recirculation mode is performed, achieving a productivity of 55 g day⁻¹ and demonstrating its potential for the efficient and scalable utilization of the electrochemical hydrocarboxylation reaction.

Amines are among the most common functional groups in bioactive molecules and pharmaceuticals, yet they are almost universally treated as synthetic endpoints. Here we report a strategy that repositions native primary, secondary, and tertiary amines as versatile handles for divergent cross-coupling. The platform relies on in situ activation via borane coordination and exploits a copper catalytic redox system that generates amine-ligated boryl radicals, which undergo beta-scission across the C(sp³)–N bond to release alkyl radicals. These intermediates engage in copper-catalyzed cross-couplings with a broad array of C-, N-, O-, and S-based nucleophiles. The method tolerates diverse amine classes, enables modular functionalization, and supports late-stage editing of complex drug scaffolds. In addition, amides can be incorporated into the manifold via reductive funneling. This work establishes a general approach to deaminative C–N bond functionalization and introduces a new logic for retrosynthetic diversification and pharmacophore remodeling.