We have developed a convenient approach to the assembly of 1,2,3-triazole-fused quinazolines through the cyclization of 5-iodotriazoles bearing a pendant sulfonamide moiety. The C(sp2)-N bond formation proceeds efficiently as a base-promoted halogen substitution in the triazole ring. The rational choice of base and solvent enables the chemodivergent synthesis of either triazole-fused quinazolines or their dihydro derivatives. The potential applications of the target heterocycles were illustrated by their involvement in Rh-catalyzed denitrogenative amidation.

Interest in metal-free hydrosilylation has grown rapidly in recent years. This surge is driven by the industrial importance of hydrosilylation, which typically relies on expensive Pt-catalysts. These catalysts lead to irreversible Pt loss and contamination of both silicone products and the environment. This work evaluates the efficiency of radical initiators, predominantly peroxides, and their applicability to a range of reagents with different natures and reactivities. This optimization identifies di(tert-butyl)peroxide (DTBP) and dicumyl peroxide (DCP) as the most effective. Reaction proceeds in the presence of 10 mol% DTBP or DCP, at 120–130 °C, at a 1:1 hydrosilane-to-alkene ratio, and does not require the use of additives or solvents. The study encompasses a wide range of terminal and internal alkenes and alkynes, including styrene and its homologues, allyl alcohol, allylamine, as well as their derivatives, allyl- and vinylsilanes, among others. The range of tertiary hydrosilanes includes alkyl-, phenyl-, silyl-, siloxy-, alkoxy-, and chlorosilanes. Additionally, the possibility of using secondary hydrosilanes, as well as gaseous reagents such as ethylene, with various hydrosilanes, including oligomeric and polymeric ones, is demonstrated. Overall, the efficiency of DTBP and DCP is assessed by obtaining more than 90 anti-Markovnikov products with yields ranging from low to quantitative levels. The process is scalable to gram quantities. Machine learning analysis revealed key reactivity trends of hydrosilanes.

High-molecular weight poly(propylene carbonate) undergoes thermal decomposition into cyclic 1,2-propylene carbonate at elevated temperatures. This process can be significantly accelerated via use of a high-temperature radical initiator or Coii/Coiii salen complexes.

We have shown for the first time that the visible-light-driven photocatalytic three-component reaction of ethyl acetoacetate, styrene, and CO2 affords two carboxylation products. The ratio of these products is determined by the CO2 pressure. Specifically, at 1.5 bar, the product ratio (4-aryl-2-acetylglutaric acid to 2-(2-aryl-3-oxobutyl)malonic acid) for unsubstituted styrene is 32:63. However, at 5.5 bar, this ratio shifts to 72:25. The impact of the substituents on the styrene ring is also noteworthy. Electron-withdrawing substituents favor the first carboxylation product, providing yields up to 95% (p-CF3, 5.5 bar CO2), while electron-donating substituents promote rearrangement, leading predominantly to the isomeric product in yields up to 71% (p-OMe, 1.5 bar CO2). The reaction proceeds at room temperature without transition metals, using an organic photocatalyst (4DPAIPN) and a base. The reaction pathway is dictated by both internal and external factors, namely the CO2 pressure and the electronic nature of the styrene substituent.

5-Iodo-1,2,3-triazoles tethered to a formyl group via an ortho-phenylene linker have been shown to be versatile precursors to a plethora of fused heterocyclic systems. The high reactivity of the aldehyde moiety toward nucleophilic addition enables in situ generation of various saturated azaheterocycles, which induces further intramolecular iodine substitution in the triazole ring. The cascade assembly of structures combining triazole, quinazoline, and cyclic aminal units occurs readily under catalyst-free conditions upon heating in ethanol. The use of chiral β-aminoalcohols allows an easy construction of enantiopure polycyclic scaffolds in a diastereoselective fashion. Chemoselective oxidative cleavage of the hemiaminal ether fragment can be performed in a one-pot manner, furnishing triazole-fused lactams.

The influence of photoreactor type (batch vs. flow) and irradiation power (450 nm, 12 W or 30 W) on the dual [Ir]/[Ni]/photoredox C(sp2)-N coupling reaction have been investigated, using the arylation of morpholine as a model reaction. The catalyst interaction, whether it is energy transfer (EnT) or single electron transfer (SET) determines the sensitivity of the system to changes in external irradiation conditions. Systems that operate via EnT are highly influenced by photoreactor configuration and irradiation power, while [Ir]/[Ni] SET systems (with an additional quencher) show greater stability under these variations. These findings demonstrate that controlling the photocatalytic process through engineering can be an effective alternative to modifying the catalyst structure, leading to more cost-effective and efficient synthetic methods.

ABSTRACT Ways to resolve the main challenges of the important industrial hydrosilylation process are proposed. Recyclable biphasic Pt/H 2 O‐ and Pt/K B r/H 2 O ‐catalysts are developed. They are prepared by dissolving K 2 PtCl 4 with or without KBr in H 2 O at r.t. for 2 min. Mechanistic studies revealed that previously unknown highly catalytically active single‐atom ( Pt/H 2 O ) or cluster ( Pt/K B r/H 2 O ) [Pt 0 ]‐complexes are generated. H 2 O, Cl – /Br – , and alkenes/alkynes coordinate such [Pt 0 ]‐species, “tuning” their stability, catalytic activity, and structure (single‐atom or cluster). The cooperation of [Pt 0 ]‐species and “on water” effect enabled high efficiency in hydrosilylation. Using Pt/H 2 O and Pt/K B r/H 2 O , a wide range of hydrosilanes, including oligomeric and polymeric ones, as well as aliphatic and aromatic alkenes and alkynes with functional groups, were employed to prepare anti ‐Markovnikov products. Pt/K B r/H 2 O made it possible to obtain cured monoliths and thin films from PDMS derivatives with Si–H‐groups, and vinylsiloxanes, dienes, including gaseous acetylene or butadiene. Pt‐free products, including cross‐linked materials can be isolated from the biphasic catalytic system by decantation. The recyclability (≥15 cycles), low Pt‐loadings and high yields enable a low E‐factor (≤0.07) and a high TON (>10 4 ). Furthermore, a constructed tube‐in‐tube flow reactor allows for effective scale‐up, automatic separation and recycling of the catalytic system with continuous product synthesis.

Homogeneous Kolbe-Schmitt carboxylation of phenoxides offers a mild and effective alternative to the classical high-temperature solid-phase Kolbe-Schmitt reaction. To develop this into a practical synthetic approach, we investigated several fundamental dependencies, particularly the impact of cations (Na, K, Li, Cs, and Rb), phenoxide concentration, and solvents (DMSO or DMF) on the yield and regioisomeric ratio of hydroxyaromatic carboxylic acids (HACAs). We identified optimal conditions for the effective carboxylation of different phenoxides, including a chiral Ellman’s sulfinamide derived from ortho-vanillin. Both solvents and cations were found to be crucial in the carboxylation of phenoxides. Due to solvation effects, DMSO directs CO2 attack to the para-position of phenoxide, while DMF, although less selective, generally affords higher HACA yields. The addition of equiv. amounts of mesitolate salt to phenoxide in either DMSO or DMF solution often drives the reaction to completion, resulting in yields of up to 98%. Phenoxides containing several EWG groups, such as halogens or alkyl groups, adjacent to the reaction center show considerably lower reactivity in carboxylation; however, by carefully adjusting parameters, acceptable conversions (>70%) can be achieved. Using the gasometry, we assessed the stability of phenoxide and mesitolate carbonate complexes in DMSO. These experiments revealed distinct stages for the onset of decomposition and carboxylation at atmospheric pressure, indicating a lower energy barrier in the homogeneous process. Further insight into carbonate complex behavior was obtained through DOSY and 13C NMR experiments, which support increased molecular association in solution and correlate with enhanced reactivity.

The phosphonylation of electron-deficient alpha-chloro-substituted nitrogen-containing heteroarenes with triethyl phosphite and triisopropyl phosphite using microwave-assisted SNAr-Arbuzov reaction was studied. The reaction proceeds at 200-270 degrees C in 30-75 min. The efficiency of the method depends on the relationship between substrate reactivity and the product stability against decomposition under the reaction conditions. It was shown that less reactive pyridine and pyrazine derivatives give low yields due to the insufficient stability of the substrates and products. In the case of 1,10-phenanthroline, quinoline, isoquinoline, quinoxaline, and pyrimidine derivatives, the phosphonylation products were obtained in 40-95% yields due to their higher stability under reaction conditions. An approach to assessing substrate reactivity using quantum chemical calculations is proposed. The reaction does not require transition metals or any other additives. Moreover, it does not affect halogen atoms at other positions of the heterocyclic system, which is beneficial for further modification of the reaction products.

This study proposes ways to resolve the main challenges of the important industrial hydrosilylation process using biphase “on water” catalytic systems. The Pt/H2O-catalytic system consists of a commercially available Pt-precatalyst, K2PtCl4, and the most naturally abundant and environmentally benign solvent, H2O. It is easily prepared by mixing them without the use of ligands or an inert atmosphere, at r.t. for 2 min. The use of affordable KBr as an additive significantly increases the efficiency of the method for a range of substrates. Mechanistic studies revealed that during hydrosilylation, single-atom complexes (mainly in Pt/H2O) and cluster (mainly, in Pt/KBr/H2O) Pt0-complexes are generated, which are responsible for the high catalytic activity of these systems. Pt/H2O- and Pt/KBr/H2O-catalytic systems are highly efficient in the hydrosilylation of a wide range of hydrosilanes, including oligomeric and polymeric ones, as well as aliphatic and aromatic alkenes and alkynes containing N-, O-, S-, Si-, and Hal-containing functional groups. The method allows for the synthesis of products in high yields with anti-Markovnikov selectivity, in air at r.t. Using the Pt/KBr/H₂O-catalytic system, cured silicone materials were obtained both as monoliths and thin films, from PDMS derivatives with Si–H-groups with linear and cyclic vinylsiloxanes, various dienes, and, more importantly, by gaseous acetylene and butadiene. Pt-free (monomer, polymer, and cured) products can be isolated from the biphasic catalytic system by simple decantation. The possibility of multiple catalyst recycling (demonstrated over 15 cycles), combined with low Pt-loadings (0.01–0.1 mol%) and high product yields (up to 99%), allows for achieving low E-factor (≤0.07) and high TON (>104). We also constructed a tube-in-tube flow reactor, which enables reaction scale-up with greater efficiency than in batch and the automatic separation of products and the catalytic system.

Abstract In this work, we have disclosed that available trifluoromethyl-substituted hydrazones derived from conjugated ynones undergo cyclization, followed by carboxylation with CO2 in the presence of K2CO3. The reaction enables the synthesis of a variety of pyrazole-4-carboxylates bearing a trifluoromethyl group in good yields under ambient conditions without the use of transition-metal catalysts. Furthermore, it was found that CF2Br-substituted ynones react with hydrazine salts in alcohols to afford hydrazones containing an alkoxycarbonyl group; these intermediates can also undergo carboxylation, providing access to pyrazole-3,4-dicarboxylates in good yields.

The efficient synthesis of ditopic N-ligands via Pd-catalyzed N,N-diarylation of 5-amino-1,10-phenanthroline with various 2-halogenosubstituted heteroarenes is reported. A series of 1,10-phenanthroline ligands containing dipyridylamine (dpa) or its analog at position 5 as an additional chelating site was obtained. Photoactive mononuclear Ru(II) and Ir(III) complexes of these ligands were prepared and characterized. X-ray diffraction and NMR spectroscopy showed that the metal in these complexes is coordinated only to the phenanthroline moiety. The chelating substituent was found not to have any significant effect on the photophysical properties of the Ru(II) center. Three Ni(II) complexes with dpa ligands, including the binuclear complexes [(bpy)2Ru(L)NiCl2](PF6)2 (L = bis(pyridin-2-yl)amino-1,10-phenanthroline), were prepared and characterized. It has been shown that these bridging ligands allow to adjust the optical and electrochemical properties of Ni(II) and Ru(II) metal centers independently, which makes them perspective for systematic modulating the Ni-centred reduction potential, while the properties of the Ru-center remain largely unaffected.

Application of trifluoroacetaldehydeN-tosylhydrazone as a new trifluoroethylating reagent for terminalalkynes is reported. This compound acts as an analog of 2,2,2-trifluorodiazoethane, devoid of suchdrawbacks as volatility, toxicity, storage instability, and explosion hazards. The CuI-mediated C-H inser-tion reaction of trifluoroacetaldehydeN-tosylhydrazone into terminal alkynes demonstrated its broadapplicability in the synthesis of trifluoroethyl-substituted acetylenes under mild basic conditions. Thismethod provides high yields and compatibility with a wide range of functional groups.

A series of novel functional polycarbonates, specifically poly(solketal glycidyl ether carbonate-co-propylene carbonate)s with varying compositions, were synthesized through the ring-opening copolymerization of solketal glycidyl ether, propylene oxide, and carbon dioxide. The reaction was catalyzed by rac-(salcy)CoIIIX complexes with bis(triphenylphosphine)iminium salts as co-catalysts, achieving high selectivity. The resulting terpolymers exhibited number-average molecular weights ranging from 2 × 104 to 1 × 105 and a narrow, bimodal molecular weight distribution, with dispersities of 1.02–1.07 for each mode. Interestingly, the addition of a small amount of water to the reaction mixture yielded a terpolymer with a unimodal molecular weight distribution and a dispersity of 1.11. Subsequent acidic hydrolysis of the solketal protective groups produced poly(glyceryl glycerol carbonate-co-propylene carbonate). All terpolymers were amorphous, with Tg near or below room temperature. The hydroxyl-functional polycarbonates underwent cyclodepolymerization under milder conditions compared to polycarbonates with protected hydroxyl groups.

A series of O-halobenzyl and O,O′-bis(halobenzyl) derivatives of (S)-1,1′-bi(2-naphthol) (BINOL) have been synthesized, and their amination in the presence of palladium and copper catalysts has been studied. As a result, a new family of macrocyclic and linear BINOL derivatives with various substituents at the oxygen atoms, including those possessing additional chiral centers, has been obtained. The synthesized compounds have been evaluated for their detecting properties toward metal cations by UV and fluorescence titration. Among the obtained open-chain derivatives, a potential fluorescent sensor for Al3+ cations has been found due to multiple emission enhancement. In addition, a fluorescent molecular probe for Hg2+ and Al3+ has been identified. Among the macrocyclic derivatives, the compound with the longest trioxadiamine linker can be used as a molecular probe for Mg2+ and Ca2+ ions due to fluorescence enhancement with a red shift, as well as for Al3+ and Hg2+ ions due to strong fluorescence enhancement without change of the position of the emission maximum.

A straightforward approach for the attachment of a nitrile moiety to the 1,2,3-triazole core has been developed. The protocol is based on the cyanation of 5-iodo-1,2,3-triazoles which are readily accessible by Cu-catalyzed azide-iodoalkyne cycloaddition. Halogen substitution occurs smoothly with KCN as a cyanide source using a Pd(0)-Dpephos catalytic system. The reaction tolerates a variety of functional groups as well as some sensitive heterocyclic scaffolds and affords the target 5-cyano-1,2,3-triazoles in yields of up to 99%. Further transformations of the nitrile group enable an easy preparation of 1,2,3-triazoles bearing diverse moieties, including amides, amines, and some azaheterocycles.

A new series of polytopic ligands based on 1,10-phenanthroline and polyoxadiamines has been synthesized through SNAr amination between 2-chloro-1,10-phenanthroline and diamines of various structures. The obtained podands were investigated as polytopic ligands for potassium and zinc ions in the industrially important reaction of cyclic carbonates synthesis from CO2 and epoxides under mild conditions (p(CO2) = 1 atm., T = 60-80 degrees C). The advantage of 1,11-diamino-3,6,9-trioxaundecane functionalized by 1,10-phenanthroline units compared to the diamine itself is demonstrated. It is revealed that heteroarylated 1,11-diamino-3,6,9-trioxaundecane can be used as a catalyst in the presence of KI (2 mol.%) with a low loading of the ligand (0.2 mol.%) instead of the usually employed 5-10 mol.% for unfunctionalized podands. Under these reaction conditions mono-substituted cyclic carbonates of various structures have been synthesized in excellent preparative yields ranging from 87 to 99%. Coordination of two Zn(II) ions to both 1,10-phenanthroline moieties has been shown to provide additional enhancement of catalytic activity. The catalysts demonstrate excellent stability and can be reused at least in 6 cycles.

In this work, we have developed an approach for direct regioselective phosphonylation of pyrazolo[1,5-a]pyrimidines in the presence of organophotocatalyst 4CzIPN under visible light irradiation to obtain a series of (pyrazolo[1,5-a]pyrimidin-3-yl)phosphonates. The discovered reaction represents the first example of direct phosphonylation of pyrazolo[1,5-a]pyrimidines. Various (pyrazolo[1,5-a]pyrimidine-3-yl)phosphonates containing both alkyl and aryl substituents at different positions were obtained in yields ranging from 39 to 95%. The use of commercially available 4CzIPN as a photocatalyst along with simple and mild reaction conditions, a wide range of substrates, the absence of heavy metals, as well as the use of clean energy, available oxidant, and a common solvent are all attractive features of this method.