Touched for the very first time! It is herein highlighted how acetaldehyde silyl enol ethers undergo enantioselective Mukaiyama aldol reaction with aliphatic and aromatic aldehydes. The chemistry relies on the use of the highly efficient and substrate-selective imidodiphosphorimidate catalyst, which displays some of the features of enzymatic catalysis.

An unknown side of boron chemistry: Similar to the nucleophilicity of boron compounds such as boryl anions and borylenes, the B−H bonding pair electrons in borane complexes also show nucleophilic properties that have led to the discovery of new chemical reactions.

Transfer news: Insertion electrochemical electrodes exhibit simultaneous electron and ion transfer, with the two transfers proceeding across different interfaces. Such three-phase electrodes give access to the Gibbs energies of electron and ion transfer of insertion electrodes.

Keep all the balls in the air: This Minireview presents recent examples in the area of mechanochemistry, in which the exertion of mechanical forces by ball milling has enabled chemical transformations with gaseous reactants, together with the technological advances that facilitated such developments.

Resistance is futile: The emergence of drug resistance has far-reaching consequences for clinical efficacy. This Review presents an analysis of the underlying structural mechanisms of drug resistance across different therapeutic indications and highlights rational approaches to overcome this threat to public health.

Catalytic functionalization/polymerization of castor oil-derived undecenol yields an aliphatic polyester in a single step under mild conditions. The key to selective formation of linear high melting polyesters is highly active carbonylation catalysts that at the same time do not undergo strong isomerization.

The charge distribution in π-stacked arene dimer cations is probed by infrared spectroscopy of pyrrole clusters. The linear correlation between the N−H stretch frequency and the positive partial charge on the pyrrole moiety (Py) is exploited to reveal subtle effects in the asymmetry of the charge distribution in the charge resonance interaction by symmetry reduction, induced either by substitution of functional groups or by solvation.

Y not rhombic? The highly improved optical spectrum of Au₄⁺ with resolved vibrational structure allows the determination of the structure of the cluster in the ground and excited states. In contradiction to all earlier assignments, the lowest-lying observable optical transition does not originate from the rhombic isomer considered most stable but from the Y isomer.

A tale of two catalysts: Two different borate catalysts for the epoxidation of aldehydes with diazoacetamides can be generated from boron and VANOL (3,3′-diphenyl-2,2′-bi-1-naphthalol). That these catalysts are different is demonstrated by a nonlinear study on the relationship of the enantiopurity of the product epoxide versus that of VANOL. Despite their structural differences, both catalysts display a similar substrate scope profile with excellent asymmetric induction for various aldehydes.

Two cats make HAM: Two distinct, mutually compatible catalysts enable the hydroaminomethylation of alkenes at or near atmospheric pressure of syngas and just 80 °C. The hydroformylation step is catalyzed by a rhodium diphosphine complex, and the reductive amination step, which is conducted as a transfer hydrogenation with aqueous, buffered sodium formate as the reducing agent, is catalyzed by a cyclometallated iridium complex.

Waste not, want not: Benzyl alcohols underwent C−C bond formation with alkynes under thermal conditions in the presence of a catalytic amount of KO^tBu to provide α-alkylated ketones with 100 % atom economy (see scheme). The reaction showed unusual regioselectivity to give products in which the C=O group was located on the side of the molecule derived from the alcohol.

A complementing Pd- and Rh-catalyzed dynamic kinetic resolution (DKR) of racemic allenes leading to N-allylated pyrazoles is described. Such compounds are of enormous interest in medicinal chemistry as drugs and drug candidates. The new methods feature high chemo-, regio- and enantioselectivity displaying a broad substrate scope and functional group compatibility. A mechanistic rational explanation for allene racemization and trans-alkene selectivity is discussed.

Switch-on functionalities: The peculiar reactivity of an As-zincosilaarsene with H₂O, NH₃, N₂O and CO₂ is reported. While the protic reagents add to the As=Si bond to give Si(X)−AsH species (X=OH, NH₂), oxidation reactions with N₂O and CO₂ give rise to the unexpected 1,2-disiloxydiarsene, arsaethynolato siloxido, and arsaketenylido siloxido zinc complexes.

The asymmetric rhodium-catalyzed alkenylation of enones and imines with arylboronic acids has been developed. A highly controllable aryl to vinyl 1,4-rhodium migration is the key step. Stereodefined vinyl moieties were installed in excellent enantioselectivies for most examined examples. DFT calculations reveal that the driving force of this rhodium migration is a kinetically favored process.

A direct cross-coupling of alkynes and allenes with amines to access α-allylated amines using a Rh/photoredox dual catalyst system was developed. Starting from easily available internal alkynes, tertiary amines, and secondary amines, various branched homoallylic amines were obtained with good to excellent yields and regioselectivity. In contrast, with a modified reaction conditions, the alkynes and terminal allenes could couple with various substituted N-aryl-tetrahydroisoquinolines smoothly affording (E)-linear homoallylic amines in good to excellent yields and regioselectivity.

Under pressure: The silicon phosphorus nitride imide SiP₂N₄NH was synthesized in a high-pressure high-temperature reaction, using HCl as a mineralizer. Its highly condensed structure is built up from SiN₆ octahedra and PN₄ tetrahedra and can be derived from a significantly distorted close-packing of nitride anions.

Terminal ynamide additions to isatins are accomplished with high yields and enantioselectivities by base-free Cu^I-bisoxazolidine catalysis. This approach provides efficient access to chimonamidines and 3-hydroxyindolinones carrying a tetrasubstituted chiral center with a synthetically versatile ynamide moiety.

An enantioselective copper-catalyzed intramolecular hydroamination reaction can be used jointly with the Suzuki–Miyaura cross-coupling to yield a diverse array of α-arylpyrrolidine scaffolds that contain pharmaceutically relevant heteroarenes with excellent enantiomeric purity under mild conditions. Furthermore, this intramolecular hydroamination strategy is applicable to the asymmetric syntheses of six- to nine-membered benzo-fused nitrogen heterocycles.

Excited-state palladium catalyzed decarboxylative alkylation of α,β-unsaturated acids is achieved by a barrierless approach under visible light irradiation at room temperature with good stereoselectivity. Detailed DFT calculations with experimental evidence suggest a neutral decarboxylative pathway.

Everything under control: New final products are observed when ether cleavage on Si(001)—the surface analogue of an S_N2 reaction—is induced by the electrons of an STM tip. The nature of these final products can be controlled by the excitation mechanism—electronic or vibrational—which in turn can be selectively addressed by the tunneling bias. PES=potential energy surface.

Swimming against the tide: A new β-diketiminate Cu^I catalyst system has been developed for C−H amidation with aroyl azides via copper nitrene intermediates. Owing to their steric bulk they target stronger, more accessible primary and secondary C−H bonds in the presence of weaker, hindered tertiary C−H bonds.

In situ X-ray absorption spectroscopy and resonant inelastic X-ray scattering at the Mn L- and O K-edges are employed to probe an operating MnO_x water oxidation catalyst. A critical step of the reaction mechanism, namely withdrawal of electron density from the O ligand shell at positive potentials, is detected and correlated with the rate-determining electron transfer process.

Polymeric carbon nitride with enhanced optical absorption and photocatalytic activities is synthesized via a one-pot ionothermal polymerization of 5-aminotetrazole in eutectic NaCl/KCl. This approach allows control of the polymerization process and tailoring of the grain boundary structure and catalytic properties.

Light on by boron: Tagging cellular proteins with carboranes enables their visualization with non-optical techniques such as nanoSIMS. Flexible protocols for the incorporation of the tags in a specific manner are shown. By combining the synthesis of carborane derivatives with biotechnological tools, high densities of the probes could be obtained inside cells, enabling relatively easy labeling and detection.

A new point of view: The magnetic hyperfine field at the ¹⁶¹Dy nucleus in Dy-containing compounds can be determined by ¹⁶¹Dy time-domain synchrotron Mössbauer spectroscopy. This quantity is influenced by the polarization of the s electrons at the ¹⁶¹Dy nucleus via metal–ligand interactions. The effect of different ligands in Dy-containing single-molecule magnets can now directly be explored from the viewpoint of the lanthanide ion.

A hydrated hydronium ion in zeolite H-MFI consists of eight water molecules and occupies a volume of 0.24 nm³, which is inaccessible for nonpolar substrates. Hydrated hydronium ions induce locally a high ionic strength resulting in a strongly nonideal environment. This destabilizes the adsorption of substrates, by lowering the heat of adsorption, but increasing the activity coefficient of the substrate.

Water repellent and light: Hydrophobic 2D Pb and Sn halide perovskites were synthesized under ambient conditions by solution-based methods and showed contact angles over 90° as well as dispersibility and photoluminescence in water, thus highlighting their hydrophobic behavior. The perovskites were also effective photocatalysts for visible-light-driven redox-neutral decarboxylation and oxidative dehydrogenation reactions.

The inner light: Elemental mapping of an osmium anticancer complex in human cancer cells, at pharmacologically relevant concentrations, using a synchrotron X-ray nanoprobe, reveals an intracellular distribution that encompasses the endomembrane system.

Early days: The first noncoinage-metal alkynyl M₄C₄ cubane has been prepared and characterized (see structure). The nanocluster contains two sets of Mn^II environments, which exhibit strong antiferromagnetic coupling. Facile amido ligand exchange and the formation of Mn nanoparticles were evaluated in catalytic studies.

In for a shock: The electric potential of a mesoporous chiral platinum phase can be tuned to allow quantitative separation of the enantiomers in a tryptophan racemate. An applied potential influences the electrostatic interactions, and thereby the enantioaffinity, between the chiral metal and the target enantiomer.

Sustainable manganese(I) catalysis enables versatile late-stage modifications of peptides, nucleotides, and drugs to give hybrid compounds with broad functional-group tolerance and ample scope.

All paths lead to Rome: By the careful design of a donor–π–acceptor ligand with both one- and two-photon absorption attributes (OPA and TPA), LPL could be triggered in an assembled metal–organic supramolecular box through either OPA or TPA pathways by several wavebands of light: UV, white (WL), and NIR (see picture). Such systems have potential for a range of applications, including anti-counterfeiting, camouflaging, decorating, and displays.

Green nylon: Use of 25 % ZrO₂/SiO₂ as catalyst allows the gas-phase ring-opening of bio-based γ-valerolactone with methanol to a mixture of methyl pentenoates containing 81 % of the 4-isomer, which could be selectively hydroformylated from the mixture to methyl 5-formyl-valerate, an intermediate for ϵ-caprolactam. The remaining isomers were converted into dimethyl adipate.

Simplest is best: Electroactive cobalt species for the oxygen evolution reaction can be prepared simply by applying an anodic bias to a mixture of a commercially available cobalt precursor and Nafion binder coated on a glassy carbon electrode. Iron dopants effectively activate the cobalt species, and most of the first row transition metals could also enhance the catalytic performance.

Play that squeezebox! Reversible switching of electrochemically controllable oligorotaxanes generates an accordion-like molecular movement. Electrochemistry, EPR, and UV/Vis-NIR studies reveal that this type of motion is induced by through-space mixed-valence, radical-cation, and Coulombic interactions between tetrathiafulvalene-decorated crown ether macrocycles.

Transmetalation, but not as you know it: A combination of kinetic studies, theoretical calculations, and microkinetic modeling showed that C₆F₅ (Pf)/C₆Cl₂F₃ (Rf) exchange between [AuPf(AsPh₃)] and trans-[RhRf(CO)(AsPh₃)₂] does not occur by typical concerted Pf/Rf transmetalation via electron-deficient double bridges. Instead, nucleophilic attack of Rh^I at the gold center triggers asymmetric oxidative insertion of Rh into the Au−aryl bond (see scheme).

[Fe]-hydrogenase (Hmd) catalyzes the hydrogenation of methenyl-tetrahydromethanopterin (methenyl-H₄MPT⁺). H₄MPT is a C1-carrier of methanogenic archaea. One bacterial genus contains the Hmd paralog, HmdII. Bacterial HmdII catalyzes the hydrogenation of derivatives of the bacterial C1-carrier, tetrahydrofolate. The crystal structure of HmdII explains the evolutionary adaptation to the different hydride-accepting substrate.

Hollow porous carbons (HPC), featuring hierarchical pores and uniform dopants of nitrogen and ultrahigh content (11.3 wt %) of single-atom Zn, are fabricated by the pyrolysis of template-directed hollow ZIF-8 spheres. Thanks to the Zn/N sites and the photothermal effect endowed by those features, the optimized HPC-800 efficiently catalyzes CO₂ cycloaddition with epoxides under light irradiation at ambient temperature.

Be my guest: A water-soluble perylene bisimide cyclophane host recognizes structurally diverse natural aromatic alkaloids by binding them in its hydrophobic cavity. Encapsulation of the guest is signalled by distinct changes in the optical properties of the host.

By fine-tuning the lithiation depth of MoS₂, the layered crystalline structure can be well preserved when cycled (3.0–0.6 V vs. Li⁺/Li), which is accompanied with the expansion of the interlayer distance. These features enable the stable cycling of commercial μm-sized MoS₂ with higher capacity and faster rate capability, making it a promising anode for fast-charging lithium ion batteries.

The thermodynamic state of H₂ adsorbed on Pt in the aqueous phase was determined via kinetic analysis of H₂ reacting with D₂O and by DFT-based ab initio molecular dynamics simulations of H₂ adsorption on Pt(111). Compared to the gas–solid interface, the presence of liquid water weakens the dissociative adsorption by decreasing the heat of adsorption and inducing a larger loss of entropy.

S marks the spot: A new class of activated vinylogous thioesters, called STEFs, were evaluated for use as biological electrophiles. These compounds, for example, enable cysteine-directed lysine conjugations by consecutive addition–elimination reactions. STEFs, as electrophilic warheads, could find broad use in chemical biology.

Mirror mirror on the wall, where has the other enantiomer gone? Catalyst 2 establishes an equilibrium between the two enantiomers 1 and ent-1 in which one enantiomer prevails (up to 55 % ee). The deracemization is responsible for the enantioselective formation of 3-cyclopropylquinolones from 3-allyl-substituted quinolones.

Small but mighty: The atom efficient and easy to synthesize reagent N-pyrrolyl alanine is shown to undergo fast and site-selective Pictet–Spengler bioconjugation. This catalyst-free conjugation strategy was successfully applied for the biocompatible, site-specific, and stable labeling of aldehydes in peptides, antibodies and, nucleic acids.

Keeping it PC: The anion [PtBu₂]⁻ reacts with CO to generate a transient intermediate with carbene character. This species undergoes either 1,2-alkyl migration or dimerization to form acyl-phosphide anions. Similarly, one of these anions reacts further with CO to give a diacyl-phosphide anion.

Nature's way: The first complete description of a DMSP biosynthetic pathway is provided by the in vitro reconstitution of four enzymes from Streptomyces mobaraensis. This pathway follows the same route as that previously described for angiosperm plants; however, this study shows that the two biosynthetic activities emerged by convergent evolution.

Stretched and Bent: Formal replacement of one Rh atom in a classical dirhodium tetracarboxylate paddlewheel complex by Bi results in a conical shape of the precatalyst: while the wide-open Bi site does not cause a racemic background reaction, the calyx-like chiral binding pocket around Rh is narrower and hence more effective. These two virtues likely synergize in asymmetric cyclopropanation reactions.

An alcohol oxidation, an oxidative condensation, intramolecular anodic olefin coupling reactions, an amide oxidation, and a mediated oxidation were all shown to be compatible with the generation and use of hydrogen gas at the cathode. This pairing of an electrolysis reaction with the production of a chemical reagent or substrate has the potential to greatly expand the use of more energy efficient paired electrochemical reactions.

Benzophenone resurrected: The inherent reactivity of benzophenone upon photochemical excitation is used for the aliphatic C−H arylation reaction. The conditions are tolerant to a broad range of functional groups. Mechanistic experiments shed light on the dual role of the new photocatalyst of the metallaphotoredox family.

Enantioconvergent cross-couplings with electrophiles that lack a directing group or a proximal p/π orbital were achieved for the first time. Specifically, a chiral nickel catalyst can accomplish Negishi reactions of racemic α-halosilanes with alkylzinc reagents with good enantioselectivity under simple and mild conditions, thereby providing access to enantioenriched organosilanes, an important class of target molecules.

Chiral silicon grease: α-Chiral silanes with no functional group (FG) in direct proximity of the asymmetrically substituted carbon atom are accessible by an enantioselective C(sp³)−C(sp³) cross-coupling of racemic α-silylated alkyl iodides and alkylzinc reagents (see Scheme). The coupling partners can be, but do not need to be, functionalized. α-Chiral silanes can thus be prepared with high modularity.

Acid-free! Bench-stable cyclohexa-1,4-diene-based hydrogen cyanide (HCN) surrogates are reported to engage in transfer hydrocyanation of alkenes upon treatment with certain boron Lewis acids. The success also depends on the equilibrium position between the intermediate isocyano- and cyanoborate isomers. Tertiary nitriles are obtained with exclusive Markovnikov selectivity.

Stretched planar peroxides: [(F₃C)₃CO]₂ and [(C₂F₅)(F₃C)₂CO]₂ were prepared from the corresponding hypofluorites and fluorinated silver wool. The solid-state structures obtained after in situ crystallisation show unusual COOC dihedral angles of 180° as well as elongated O−O bonds because of the bulky perfluorinated alkyl groups. In addition, they are insensitive to both impact (>40 J) and friction (>360 N).

Golden diversity: Readily available sulfilimines were successfully applied as versatile nitrene transfer reagents. By trapping the resulting α-imino gold carbenes with divergent functionalities, four different types of aza-heterocycles (indoles, 3-azabicyclo[3.1.0]hexan-2-imines, quinolines, and imidazoles) were prepared in high efficiency.

Heck-type arylation of cyclopropanated furans and pyrroles proceeds with ring expansion via the unactivated cyclopropyl bond, giving rise to arylated diyhdropyridines, pyridines, and 2H-pyrans.

A universal strategy for the monotopic and bitopic functionalization of graphene is presented. This process employs aryl radical species generated by acid-induced decomposition of arylazocarboxylic acid tert-butyl esters (ArN₂Boc) under mild conditions and is directed by defect sites.

More than one wavelength to form a bond: A set of λ-orthogonal photoligations has been established that enables selective intrachain coupling and interchain ligation of one parent polymer. Importantly, both reactions can be triggered in either sequence by different colours of light.

Only a click away: A supramolecular click procedure analogous to a ball detent mechanism (see figure) leads to a helical columnar liquid-crystalline separated donor–acceptor antenna system. Two shape-persistent star mesogens are used: one provides the free space and the other is sterically encumbered by four fullerenes.

Neutral at last: Silicon tris(perchloro)dioxolene, a neutral diradical with triplet ground state, was obtained by reacting perchloro-o-quinone with silicon tetraiodide. This is the first example of magnetic coupling across hexacoordinate silicon and of a non-metal center that bridges two open-shell semiquinonates.

Small organic molecules on ice and water surfaces play crucial roles in many environmentally relevant processes. Surface-specific vibrational spectroscopy was combined with a controllable flow cell apparatus to investigate the molecular adsorption of acetone onto the basal plane of single-crystalline hexagonal ice with a large surface area.

All good things come in threes: Reactions of an Al^I nucleophile with B^III species leads to three distinct modes of reactivity: adduct formation (Al^I-B^III), oxidative addition (Al^II-B^II), and reduction (Al^III-B^I). IMes=1,3-dimesitylimidazol-2-ylidene, TerPh^iPr=bis-2,6-(2,4,6-triisopropylphenyl)phenyl.

An iron porphyrin catalyst furnishes acetonitrile-functionalized indole derivatives by C−H functionalization reactions of protected and unprotected indole heterocycles with diazoacetonitrile. This process streamlines the synthesis of valuable tryptamines for applications in total synthesis and drug discovery.

A matter of spin: The [NbN]⁺/[ONbN]⁺ system catalyzes the oxidation of CO through N₂O. In contrast, in the [Nb]⁺/[NbO]⁺ and [NbO]⁺/[Nb(O)₂]⁺ systems, [Nb]⁺ and [NbO]⁺ are oxidized by N₂O, even though neither [NbO]⁺ nor [Nb(O)₂]⁺ react with CO at room temperature. The origins of the distinctly different reactivities are addressed by quantum chemical calculations.

Small but effective: Chemically induced dimerization usually requires large, bifunctional molecules. A small, covalent, monovalent inhibitor efficiently induces dimerization of an essential oxidoreductase from the parasite Trypanosoma brucei, the agent causing African Sleeping Sickness, through elaborate intra- and intermolecular interactions.

Biofilm star: A multifunctional zwitterionic pillar[5]arene shows antibacterial ability against Gram-negative Escherichia coli (DH5α) and Gram-positive Staphylococcus aureus (SH1000) bacterial strains in solution. It also showed activity towards established biofilms and killed the biofilm-enclosed cells without rapid generation of resistance.