4-(2-Aminophenyl)-3-yn-1-ols are selectively transformed into high value added 3,5-dihydrofuro[3,2-c]quinolin-4(2H)-ones by a PdI₂-catalyzed sequential 5-endo-dig O-cyclization – N-cyclocarbonylation process under oxidative conditions.

Comprehensive Summary

The PdI₂/KI-catalyzed oxidative carbonylation of 4-(2-aminophenyl)-3-yn-1-ols, bearing two potential nucleophilic groups in suitable position selectively leads to dihydrofuroquinolinone derivatives in fair to high yields (60%—89%) and excellent turnover numbers (180—267 mol of product per mol of Pd) over 19 examples, through a mechanistic pathway involving initial O-cyclization followed by N-cyclocarbonylation. In such process, the selective catalytic construction of two rings and three new bonds is achieved in one synthetic step to afford high value added fused heterocyclic structures starting from readily available materials.

Comprehensive Summary

A phosphine-catalyzed [4+3] annulation between dinucleophilic indole derivatives and Morita−Baylis−Hillman (MBH) carbonates was discovered by using the N1 and N4′/C4′ nucleophilicities of the indole precursors, in which indoles act as four atom synthons. This protocol provides an efficient and facile access to indole-1,2-fused 1,4-diazepinones and azepines in good to high yields in one step, which illustrates potential synthetic utilities in drug discovery.

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Comprehensive Summary

In this paper, we have developed a decarboxylative amination of carboxylic acids with nitroarenes for the synthesis of secondary amines. The protocol is performed at mild conditions without the use of noble metals as catalysts. A wide range structurally diverse secondary amines could be obtained in good yields (up to 94%) with good functional group tolerance. This transformation shows good to excellent selectivity, avoiding the generation of overalkylated byproducts.

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Herein, we report that the dehydration process of lantibiotic cacaoidin involves a dehydratase complex, which is composed of a phosphotransferase CaoK and a lyase CaoY in a 1 : 1 molar ratio. We show that fusing CaoK to CaoY enables the resulting enzyme CaoYK to exert enhanced solubility and dehydration activity.

Comprehensive Summary

Dehydration of serine/threonine residues necessitates the activity of a dehydratase enzyme (domain) during the biosynthesis of RiPP. Recently, it was reported that dehydration in the thioviridamide pathway relies on a distinct dehydratase complex that showcases the activities of a phosphotransferase TvaC for serine/threonine phosphorylation and a lyase TvaD for subsequent phosphate elimination. Herein, we report that dehydration reactions in the pathway of lantibiotic cacaoidin involves a similar dehydratase complex, CaoK/CaoY. Remarkably, this dehydratase complex exhibits flexible enzymatic activity and tolerates significant variations in its substrate peptide sequence. By binding with the leader peptide (LP) sequence of precursor peptide CaoA, the dehydration reactions proceed in a directional manner from the C-terminus of the core peptide (CP) to the N-terminus, and C-terminally truncated variants of CP are acceptable. We show that fusing CaoK to CaoY in a 1 : 1 molar ratio enables the resulting enzyme CaoYK to exert enhanced dehydration activity. CaoK binds with the LP to improve its own solubility and to ensure the phosphate transfer activity, while CaoY functions in a manner independently of LP. This work advances our understanding of the dehydration process during cacaoidin formation, and provides useful enzymes and methods for the studies of the rapidly emerging RiPPs.

Comprehensive Summary

Oxidative dehydrogenation of propane has been an ever-growing field for propylene production due to its exothermic properties, of which overoxidation is the major drawback, with CO and even CO₂ as undesired by-products. For the purpose of getting higher propylene selectivity as well as yield, herein we report Ni single atoms supported on calcium aluminate as an efficient catalyst candidate for propane oxidative dehydrogenation. Beneficial from higher valence states of Ni₁ species, it shows 2~3 times as much propylene selectivity as that of Ni nanoparticles. About 14.2 % C₃H₆ yield with 47.3 % propylene selectivity have been achieved on the 2% Ni single atom catalyst and a good stability during 20 h test can be obtained as well.

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Comprehensive Summary

A photocatalytic [3+2] annulation of alkenes with vinyl azides was developed under irradiation by visible light in the presence of organic dye photocatalysts. This broad substrate scope and high functional group tolerance were demonstrated by more than 50 examples. The reaction provides a novel and efficient method for the synthesis of polyfunctionalized pyrroles under very mild metal-free conditions without other additives.

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Comprehensive Summary

The development of host-guest MOF luminescent composites has attracted considerable attention. However, it is still a challenge to reasonably design large scale conjugated polycarboxylic acids metal-organic framework (MOF) and modulate donor-acceptor interaction. Herein, a series of isostructural 3D porous lanthanide MOF [Ln₂(BINDI)_0.5(NO₃)(DMA)(H₂O)]∙DMA∙2.5H₂O (Ln = La (1), Ce (2), Pr (3) and Nd (4); H₄BINDI (N, N’-bis(5-isophthalic acid)-1,4,5,8-naphthalenediimide) were synthesized. Considering the electron-deficient performances of Ln-BINDI MOFs, D-A type composites Ln-MOFs (1-4@H₄TBAPy) were prepared via the incorporation of electron-rich H₄TBAPy (1,3,6,8-Tetrakis(p-benzoic acid) pyrene), which more improved the luminescence performance of complexes 1-4 and can be used as fluorescence sensors for the detection of nitro compounds and aldehydes. High sensitivity of 1@H₄TBAPy towards pNBA, pNA PNP, DNP, and TNP could be achieved through hydrogen bond interactions between MOF and analytes, as well as the π-π interaction between H₄TBAPy and the naphthalene ring of BINDI, thus the fluorescence quenching efficiency of 1@H₄TBAPy better than that of the complex 1. In addition, it is found that 1@H₄TBAPy has high selectivity and sensitivity to aromatic aldehyde SA, 5-Mesal and HMBA. Such strategy to enhance the emission of NDI based Ln-BINDI MOFs, which will open up an avenue to obtain more fluorescent MOFs for sensing.

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Comprehensive Summary

N-methylation of amines with CO₂ and H₂ is a potential approach for CO₂ utilizations because N-methylated amines can be used as solvents and organic intermediates. In₂O₃-supported Cu (Cu/In₂O₃) is acted as an effective heterogeneous catalyst for N-methylation reaction of N-methylaniline (MA) with CO₂ and H₂, showing higher N,N-dimethylaniline (DMA) selectivity than other supported Cu catalysts. On the one hand, the dispersion of Cu can be improved by the defective In₂O₃ support. On the other hand, In₂O₃ support is active in the dissociative adsorption of CO₂ through C–O bond breaking. In addition, the H₂ dissociation ability of In₂O₃ can also be enhanced by Cu. The combination of Cu and In₂O₃ is effective in the activation of CO₂, the adsorption of intermediate N-Methylformanilide (MFA), the hydrogenation of MFA to DMA and the prohibition of C−N bond cleavage side reactions, thereby enhancing the reaction rate of MA conversion and the selectivity to DMA.

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The chirality transfer from a natural chiral biosource to achiral azobenzene polymers is developed based on the simple and efficient spin-coated film. The annealing treatment, the content of chiral inducer and the molecular weight of the Azo polymer are key to the induction of supramolecular chirality by cellulose derivatives. The corresponding chirality-inducing mechanism was demonstrated to arise from the aggregation chirality induced by the C-H/O=C and C-H/π interactions between the glucose repeating units and the PMMAzo polymer side-chains.

Comprehensive Summary

Various optically active polymers are known to afford sophisticated chirality-related functionalities, i.e., asymmetric catalysis, chiroptical switching and memory in UV-vis-NIR region, chromatographic separation of enantiomers, and sensors for molecular chirality. Recently, material researchers have paid much attention to the design of chiral supramolecular architectures from achiral polymers upon intermolecular interactions with help of greener biosources. The present article reports an instantaneous generation of ambidextrous supramolecules revealing light-driven chiroptical switching/memory in UV-vis region when achiral azobenzene-containing vinylpolymers are non-covalently interacted with alkyl ester derivatives of natural cellulose and D-/L-glucose. It was recognized that the semi-synthetic biomaterials efficiently work as chirality-inducing scaffoldings to several achiral and optically inactive molecules, oligomers, and polymers. Our successful results shed light on a new approach of how inexpensive poly-/mono-saccharide derivatives can afford supramolecular chiroptical systems with the azobenzene pendant polymer as aggregates in suspension and liquid-crystalline films with minimal energy, time, and cost.

We demonstrate a novel electrocatalytic strategy for selectively hydrogenating alkynols to corresponding high-value-added alkenols under ambient temperature and pressure. In acidic solution, the as-fabricated Cu₃P nanoarrays on Cu foam exhibit high alkynol conversion, high alkenol selectivity, and superior long-term stability at an industrial-level current density.

Comprehensive Summary

Alkenols are important intermediates for the industrial manufacture of various commodities and fine chemicals. At present, alkenols are produced via thermocatalytic semihydrogenation of corresponding alkynols using precious metal Pd-based catalysts in pressurized hydrogen atmosphere. In this work, we highlight an efficient electrocatalytic strategy for selectively reducing alkynols to alkenols under ambient conditions. Using 2-methyl-3-butyn-2-ol as a model alkynol, Cu₃P nanoarrays anchored on Cu foam remarkably deliver an industrial-level partial current density of 0.79 A·cm^–2 and a specific selectivity of 98% for 2-methyl-3-buten-2-ol in acidic solution. Over a 40-runs stability test, Cu₃P nanoarrays maintain 90% alkynol conversion and 90% alkenol selectivity. Even in a large two-electrode flow electrolyser, the single-pass alkynol conversion and alkenol selectivity of Cu₃P nanoarrays exceed 90%. Moreover, this selective electrocatalytic hydrogenation approach is broadly feasible for the production of various water-soluble alkenols. Electrochemical analyses, theoretical simulation and electrochemical in-situ infrared investigations together reveal that exothermic alkynol hydrogenation, facile alkenol desorption and formation of active H on Cu₃P surfaces account for the excellent electrocatalytic performance.