Propionate side chains are essential structural componentsof porphyrin-basedmetalloenzymes. While numerous studies have investigated the functionalsignificance of propionate side chains from various perspectives,comprehensive reviews focusing specifically on their roles in catalyticmechanisms remain scarce. Traditionally, the role of propionate hasbeen limited to substrate binding and heme stabilization; however,emerging evidence from studies published particularly after 2005 highlightsits involvement in a range of noncanonical functions, including watergating, oxidant formation, and electron transfer. This review aimsto bridge the gap in existing literature by systematically discussingthese expanded roles and emphasizing the broader mechanistic importanceof propionate side chains in metalloenzymes, particularly the iron-containingenzymes.

This review comprehensively summarizes the recent advancesin thedirect C–H perfluoroalkyl thiolation and perfluoroalkyl sulfonylation,focusing on the incorporation of −SCF3 and −SO2CF3 motifs. Due to their exceptional lipophilicity,electron-withdrawing nature, and metabolic stability, these fluorine-containinggroups are highly valuable in pharmaceutical, agrochemical, and materialsciences. The contents of this review are systematically organizedaccording to the hybridization of the central carbon atom (sp, sp2, sp3) and cover both transition-metal-catalyzedand transition metal-free methodologies. Key developments in electrophilictrifluoromethylthiolating reagents, such as hypervalent iodine compounds, N-trifluoromethylthiosaccharin, and related derivatives,are highlighted. The mechanism, scope, limitation, and applicationof typical reactions are discussed, emphasizing strategies to overcomechallenges in regioselectivity and functional group compatibility.The review also explores emerging trends in photocatalytic, electrochemical,and dual catalytic systems, underscoring the move toward more sustainableand efficient synthetic routes. Finally, future perspectives and potentialapplications in the synthesis of bioactive molecules and functionalmaterials are discussed.

Taming radical anionswith highly electropositive metal ions posesa grand synthetic challenge owing to the high reactivity of such compoundsoriginating from the unpaired electron. A successful synthetic metalradical match elicits a desire to thoroughly understand the electronicstructure of a given metal radical pairing, which may inform aboutthe potential physical properties pertaining to spintronics and magnetismrelevant for future technologies. Here, the 1,4,5,8-tetraazanaphthalene(tan) ligand was utilized in the synthesis of (Cp*2Y)2(μ-tan), 1, using the doubly reduced versionK2tan and Cp*2Y­(BPh4) following asalt metathesis reaction. Chemical oxidation of 1 yielded[(Cp*2Y)2(μ-tan•)]­[BArF20], 2, containing a tan–• radical anion. 2 constitutes the first d-block coordination compound bearing a tan radical. 1 and 2 were studied through X-ray crystallography, electrochemistry,and spectroscopy. The radical nature of 2 was uncoveredby cw-EPR spectroscopy and density functional theory (DFT) computations.All findings suggest major changes in the spin and charge distributionsof this organic radical ligand when it is metalated. In fact, theresults demonstrate that the tan–• radicalis more stable when coordinated to a transition metal than in itsfree nature, and thus, this insight is relevant for the developmentof future spintronic technologies.

The use of heterogeneous catalysts to generate aminecompoundsthrough anaerobic N-alkylation of alcohols via hydrogentransfer strategy is a highly promising synthetic strategy, as itcan construct C–N bonds under relatively mild and green conditions.Moreover, amine compounds are widely used in the synthesis of pharmaceuticalintermediates, agriculture and fine chemicals. In this work, we successfullyconstructed a novel Co3O4/CeO2 catalystusing the hydrothermal synthesis method and applied it to the N-alkylation reaction of alcohols, achieving up to 99% ofthe target product yield with broad substrate scope and high catalyststability. The Ce3+/Ce4+ redox pairs and oxygenvacancies in the CeO2 support with highly dispersed Cospecies synergistically catalyze the hydrogen borrowing process ofalcohols and amines to generate secondary amines with high activityand selectivity.

We report the design, synthesis, and conformational analysisoftwo aryl-extended calix[4]­pyrrole (AE-C[4]­P) cavitands that featurea single methylene bridge and an opposed aromatic bridging wall withan inward-facing carboxylic acid. Inspired by Rebek’s introvertedacid motif, these cavitands were developed to explore guest-inducedconformational switching between “equatorial” and “axial”orientations of the bridging aromatic wall. Binding studies with N-oxide guests, capable of monotopic or ditopic hydrogenbonding, revealed that the nature of the bridging aromatic spacercritically governs the host behavior. The benzimidazole-based cavitandshowed strong affinity for DABCO mono-N-oxide butresisted conformational change. In contrast, the quinoxaline–imidazoleanalogue underwent a solvent-dependent switch from “equatorial”to “axial” geometry upon binding 4-carboxy-pyridine-N-oxide guest. This switching is driven by the ditopic bindingof the guest and stabilized by two intramolecular CH···lonepair interactions in the axial conformer of the complex. DFT calculationssupported the experimental results. The reported findings highlightkey structure–function relationships in calix[4]­pyrrole cavitandsand establish a general strategy for designing guest-responsive molecularcontainers capable of conformational switching.

A novel copper­(I)-anchoredcovalent organic polymer (Cu+@COP) is presented as a robust,heterogeneous catalyst for copper-catalyzedazide–alkyne cycloaddition (CuAAC), operating without the needfor external reducing agents or observable copper leaching. Cu+ stabilization is achieved via multidentate N,O-ligand coordinationwithin the polymer matrix, enabling high catalytic efficiency (upto 95% yield) and recyclability. Structural, spectroscopic, and ICP-OESanalyses confirm Cu presence, offering an alternative to traditionalCuAAC protocols. This system combines operational simplicity, reducedwaste, and green chemistry principles, positioning Cu+@COPas a practical catalyst for applications in synthetic and materialschemistry.

Phosphine-mediated nucleophilic substitution reactionsof alcoholsubstrates, such as the Appel and Mitsunobu reactions, have foundwidespread applications in chemical synthesis. However, their relianceon stoichiometric chemical oxidants (e.g., carbon tetrachloride andazodicarboxylate reagents) often results in limited functional grouptolerance, environmentally hazardous wastes, and unsatisfactory reactioneconomy. Herein, we describe a user-friendly electrochemical Appelreaction employing readily available tetrabutylammonium halide salts(nBu4N+X–, X = Cl, Br, and I) as the halogen source. A survey of alcohol substratesrevealed broad functional group tolerance, including complex pharmaceuticaland bioactive scaffolds. Electroanalytical voltammetry and controlexperiments support a halide-coupled phosphine oxidation pathway undermild anodic potentials, affording key alkoxyphosphonium intermediatesprior to nucleophilic substitution. Notably, the electrochemical halogenationconditions can also facilitate intramolecular alcohol etherificationwith oxidation-sensitive phenols and weakly acidic alcohol nucleophiles.

Carbofunctionalization of alkynes with trifluoromethylsulfonatenucleophiles is a powerful strategy for the synthesis of vinyl triflateswith diverse molecular complexity. However, stereoselective protocolsare challenging to realize, and the development of novel strategiesfor controlling the selectivity is highly desirable. In this work,we show that gold complexes bearing the hemilabile MeDalPhos ligand(MeDalPhos = di­(1-adamantyl)-2-dimethylamino-phenylphosphine) catalyzethe E-stereoselective carbofunctionalization of internalalkynes using aryl/vinyl iodides and AgOTf as simple starting reagents.Based on the outer-sphere nature of this reaction and the beneficialeffect of the MeDalPhos ligand, the Z-selective attackis practically suppressed, leading to an ideal kinetic selectivity.Mechanistic studies, both experimental and theoretical, revealed thatthe interplay between kinetics and thermodynamics is crucial in determiningthe final E/Z ratios for each substrate.

Selective functionalization of C­(sp3)–Hbondsremains challenging yet crucial for researchers. A frequently usedapproach by chemists to tackle this challenge involves leveraging1,2-metal migration/insertion, which enables the selective activationand cleavage of a specific C­(sp3)–H bond adjacentto or distant from the directing group. Palladium is among the mostcommonly employed catalysts for C­(sp3)–H functionalizationthrough metal migration/insertion, with Pd­(OAc)2 beingthe predominant palladium complex utilized in these processes. 1,2-Palladiummigration is a key strategy for achieving selective C­(sp3)–H functionalization. After palladium coordinates to a directinggroup, its migration can activate the nearby C­(sp3)–Hbond. With subsequent migrations, more distant C­(sp3)–Hbonds can be targeted and transformed into C­(sp3)–functionalgroups. During the 1,2-insertion of palladium, the migration of palladiumtakes place following the activation of the C­(sp3)–Hbond. This migration step typically involves the palladium insertinginto a double bond, which links the C­(sp3)–H bondto a C­(sp2)–H bond, thereby progressing the reaction.Ultimately, this review highlights that C­(sp3)–Hfunctionalization via 1,2-palladium migration/insertion has the potentialto selectively modify both proximal and remote C–H bonds inorganic molecules, offering a valuable tool for researchers to synthesizea wide range of organic compounds in future studies. This accountencompasses all types of 1,2-palladium migration/insertion and examinestheir impact on C­(sp3)–H functionalization. It providesa detailed analysis of the mechanisms involved and explores how thesemigrations enable the activation of both remote and proximal C­(sp3)–H bonds with the directing group.

CationicAu­(I) complexes of indoles embedding Buchwaldphosphineligands are described. A study combining NMR and X-ray crystallographyis described in order to understand the nature of the coordinationof the cationic Au atom to the C2–C3 double bond of indoles.Our studies reveal an intermediate coordination between η2 and η1, demonstrated by a strong sp3 character of the C3 atom and a significant slippage towardthe C3 atom of the indole rings.