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In this study, the homogeneous carboxylation of potassium, sodium, and lithium phenolates in DMSO solution at 100 °C by the Kolbe-Schmitt reaction was investigated. The impact of water, phenolate concentration, and cation nature on the yield of products and reaction selectivity was demonstrated. Based on the patterns observed, it was concluded that a complex cluster mechanism governs the carboxylation reaction in the solution. The use of a homogeneous reaction medium allowed for convenient testing of various additives to assess their impact on the reaction. Basic additives such as sodium salts of mesitol, tert -butylcalix[4]arene, sodium isopropyl, and tert -butyl cabonates were found to enhance the reaction, increasing the yield of hydroxybenzoic acids by 20% (to 61.6%). The main product in the DMSO solution was identified as 4-hydroxybenzoic acid, in contrast to the classical Kolbe-Schmitt method which typically yields 2-hydroxybenzoic (salicylic) acid. The use of 13 C NMR spectroscopy enabled the observation of a "carbonate complex" in the solution for the first time, with the carbonate carbon displaying a chemical shift value of 142 ppm, an unusual finding for stable carbonates, and located between the signals of free dissolved CO 2 and carboxylate derivatives.

Photoredox-catalyzed phosphonylation of bromo-substituted 1,10-phenanthrolines under visible light irradiation was studied. The reaction was shown to proceed under mild conditions with Eosin Y as a photocatalyst in DMSO under blue light irradiation. It is transition-metal-free and affords the target phosphonate-substituted 1,10-phenanthrolines in moderate yields (26-51%) in 22 to 40 h. The rate and selectivity of the reaction depend largely on the position of the bromine atom, as well as on the nature and position of other substituents in the 1,10-phenanthroline core.

The simple approach of increasing the elastic properties of atactic poly(propylene carbonate) (PPC) with Mn = 71.4 kDa, ĐM = M w /M n = 1.86, and predominantly carbonate units (>99%) is suggested by selecting the appropriate hot pressing temperature for PPC between 110 and 140 °C. Atactic PPC is synthesized through ring-opening copolymerization of ( rac )-propylene oxide and CO 2 mediated by racemic salen complex of Co(III). Hot pressing PPC results in the release of a small amount of propylene carbonate (PC), sufficient to lower the glass transition temperature from 39.4 to 26.1 °C. Consequently, increasing the pressing temperature from 110 to 140 °C generates materials with a reduced modulus of elasticity (from 1.94 to 0.09 GPa), yield strength (from 38 to 2 MPa) and increased tensile elongation (from 140 to 940%). Thermomechanical analysis has shown a significant expansion in sample volume by hundreds of percent within the 80-130 °C range. PPC also displays large, reversible deformations, which can be utilized by creating shape memory materials., Competing Interests: The authors declare no conflicts of interest.

Divergent access to bicyclo[3.1.0]hexane and cyclopenta[ c ]pyrazole scaffolds bearing azole and azine units has been developed. The approach involves intramolecular cyclization of 5-iodo-1,2,3-triazoles acting as stable diazoimine precursors with concomitant noncatalytic (3 + 2)-cycloaddition. The choice of solvent allows control of the outcome of the cascade transformation. The developed procedure is simple and cost-efficient and allowed important heterocycles to be obtained in one-pot with various functional groups.

Dinuclear complexes bearing Ru(II) photoactive centers are of interest for the development of efficient dual catalysts for many photocatalyzed reactions. Ditopic polypyridine ligands, bis(pyridin-2-yl)amino-1,10-phenanthrolines, containing an additional coordination site (bis(pyridin-2-yl)amine, dpa) at positions 3, 4 or 5 of the 1,10-phenanthroline core (Phen-3NPy2, Phen-4NPy2 and Phen-5NPy2) were synthesized. They were used as bridging ligands to obtain dinuclear complexes [(bpy) 2 Ru(Phen-NPy2)PdCl 2 ](PF 6 ) 2 (Ru(Phen-NPy2)Pd) in good yields via stepwise complexation. In these complexes Ru(II) is coordinated to 1,10-phenanthroline, while Pd(II) is bound to the dpa chelating moiety, as established by NMR spectroscopy and X-ray single crystal analysis. The influence of the position of dpa in the phenanthroline ring on the structural, optical and electrochemical properties of Ru(Phen-NPy2)Pd complexes was studied. The complexes exhibit photoluminescence in argon-saturated MeCN solution with maxima in the range of 615-625 nm, with emission quantum yields ranging from 0.11 to 0.15 for Ru(Phen-NPy2) complexes and from 0.018 to 0.026 for dinuclear Ru(Phen-NPy2)Pd complexes. All the complexes absorb visible light in the range of 370-470 nm with high extinction coefficients and can be considered useful as photocatalysts. The Ru 2+/3+ potential in Ru(Phen-NPy2)Pd complexes showed no significant dependence on the dpa position, while the Pd 2+/0 reduction potential was significantly lower for Ru(Phen-3NPy2)Pd and Ru(Phen-4NPy2)Pd, than for Ru(Phen-5NPy2)Pd (-0.57 V and -0.72 V vs. Ag/AgCl, KCl (sat.) , respectively). The complexes were used as photoactivated precatalysts in Cu-free Sonogashira coupling under blue LEDs (12 W) irradiation. The reaction proceeded roughly three times faster when Ru(Phen-4NPy2)Pd and Ru(Phen-3NPy2)Pd were used as catalyst precursors compared to the mixed catalytic system Ru(bpy) 3 (PF 6 ) 2 /(RNPy 2 )PdCl 2 .

A comparative study of the copolymerization of racemic propylene oxide (PO) with CO 2 catalyzed by racemic (salcy)CoX (salcy = N , N '-bis(3,5-di- tert -butylsalicylidene)-1,2-diaminocyclohexane; X = perfluorobenzoate (OBzF 5 ) or 2,4-dinitrophenoxy (DNP)) in the presence of a [PPN]Cl ([PPN] = bis(triphenylphosphine)iminium) cocatalyst is performed in bulk at 21 °C and a 2.5 MPa pressure of CO 2 . The increase in the nucleophilicity of an attacking anion results in the increase in the copolymerization rate. Racemic (salcy)CoX provides a high selectivity of the copolymerization, which can be higher than 99%, and the living polymerization mechanism. Poly(propylene carbonate) (PPC) with bimodal molecular weight distribution (MWD) is formed throughout copolymerization. Both modes are living and are characterized by low dispersity, while their contribution to MWD depends on the nature of the attacking anion. The racemic (salcy)CoDNP/[PPN]DNP system is found to be preferable for the production of PPC with a high yield and selectivity.

An approach to the synthesis of phosphoryl substituted spiro-1,3-dioxolane oxindoles was developed from the base-catalyzed reaction of various isatins with (3-hydroxyprop-1-yn-1-yl)phosphonates. It was found that various aryl-substituted and N-functionalized isatins with the formation of appropriate products with high yields and stereoselectivity when using t -BuOLi are able to react. Cytotoxic activity evaluation suggests that the most significant results in relation to the HuTu 80 cell line were shown by N-benzylated spirodioxolanes. 5-Cloro- N -unsubstituted spirooxindoles exhibit antiaggregational activity exceeding the values of acetylsalicylic acid.

The development of luminescent molecular materials has advanced rapidly in recent decades, primarily driven by the synthesis of novel emissive compounds and a deeper understanding of excited-state mechanisms. Herein, we report a streamlined synthetic approach to light-emitting diazapolyoxa- and polyazamacrocycles N 2 C n O x Q and N y C n Q ( n = 3-10; x = 2, 3; y = 2-5), incorporating a 2,3-diphenylquinoxaline residue (DPQ). This synthetic strategy based on macrocyclization through Pd-catalyzed amination reaction yields the target macrocycles in good or high yields (46-92%), enabling precise control over their structural parameters. A key role of the PhPF- t Bu ligand belonging to the JosiPhos series in this macrocyclization was elucidated through DFT computation. This macrocyclization reaction eliminates the need for complex protecting-deprotecting procedures of secondary amine groups, offering a convenient and scalable method for the preparation of target compounds. Moreover, it boasts a potentially broad substrate scope, making it promising for structure-properties studies within photophysics, sensor development, and material synthesis. Photophysical properties of representative macrocycles were investigated, employing spectroscopic techniques and DFT computation. It was demonstrated that DPQ-containing macrocycles display aggregation-induced emission in a DCM-hexane solvent mixture despite the presence of flexible tethers within their structures. Single-crystal X-ray diffraction analysis of a representative compound N 2 C 8 O 3 Q allowed us to gain deeper insight into its molecular structure and AIE behaviour. The emissive aggregates of the N 2 C 10 O 3 Q macrocycle were immobilized on filter paper yielding AIE-exhibiting test strips for measuring acidity in vapors and in aqueous media.

Ru(II) complexes with polypyridyl ligands (2,2'-bipyridine = bpy, 1,10-phenanthroline = phen) play a central role in the development of photocatalytic organic reactions. In this work, we synthesized four mixed-ligand [Ru(phen)(bpy) 2 ] 2+ -type complexes (Ru-Pcat-A) bearing two phosphonate substituents P(O)(OH)(OR) (R = H, Et) attached to the phen core at positions 3,8 (Ru-3,8PH and Ru-3,8PHEt) and 4,7 (Ru-4,7PH and Ru-4,7PHEt) of the heterocycle in high yields (87-99%) and characterized them using spectral methods. Single crystal X-ray diffraction was employed to determine the coordination mode of the ditopic phen ligand in Ru-4,7PH. This complex exists as the neutral species and forms a 1D hydrogen-bonded framework in the crystals. The light absorption characteristics were found to be similar for all complexes prepared in this work. However, the emission maxima in aqueous solutions were significantly affected by the substitution of the heterocycle, ranging from 629 nm for Ru-4,7PH to 661 nm for Ru-3,8PHEt. The emission quantum yields in Ar-saturated deionized water showed a strong dependence on the substitution pattern of the phen ligand, with maximal values reaching approximately 0.11 for Ru-4,7PHEt and Ru-4,7PH, which is twice as high as that of the classical [Ru(bpy) 3 ] 2+ complex (Ru-bpy). The photocatalytic performance of Ru-Pcat-A was investigated using visible light photoredox catalytic transformations of tertiary amines. With Ru-Pcat-A, we achieved the phosphonylation of N -aryl-1,2,3,4-tetrahydroisoquinolines (THIQs) and cyanation of THIQs and N , N -dimethylaniline in methanol, while a mixture of nitromethane/methanol (1 : 1 v/v) proved to be the optimal solvent for conducting the nitromethylation of THIQs. In the majority of the studied reactions, Ru-4,7PHEt exhibited greater efficiency compared to Ru-bpy, and it could be easily separated from the products using water extraction and reused in the next catalytic cycle. We successfully performed seven consecutive nitromethylation and phosphonylation of N -phenyl-1,2,3,4-tetrahydroisoquinoline using the recycled homogeneous photoredox catalyst.

In this work, we have developed selective methods for the synthesis of quinoline-2-carboxylates and quinoline-3-carboxylates as well as (indolin-2-ylidene)acetates through copper-, silver-, or phosphine-catalyzed reaction of propiolates with 2'-amino-2,2,2-trifluoroacetophenones. The approaches proposed ensure synthesis of substituted quinoline carboxylates and (indolin-2-ylidene)acetates in good yields. Introduction of alkynones into the reaction with 2'-amino-2,2,2-trifluoroacetophenones gives acyl substituted derivatives in good yields., (© 2023 Wiley-VCH GmbH.)

The reaction of direct photoinitiated iodosulfonylation of internal acetylenes with p -tolylsulfonyl iodide and its regioselectivity of the products was studied. Methods for the subsequent functionalization of β-iodovinylsulfones using cross-coupling reactions to obtain valuable and non-available compounds are proposed.

In this study, we developed a selective method for synthesis of multi-substituted quinoline-2-ylphosphonates and quinoline-3-ylphosphonates by copper- or gold-catalyzed reactions of phosphoryl-substituted conjugated ynones with 2'-amino-2,2,2-trifluoroacetophenones. The approach proposed makes it possible to obtain various substituted quinolines in good yields. It is also shown that (4,4,4-trifluoro-3-oxobut-1-yn-1-yl)phosphonate reacts with 2-aminoaryl ketones under non-catalytic conditions with formation of 4-substituted quinoline-2-ylphosphonates in high yields.

Synthetic approach to fluorescent polyaza- and polyoxadiazamacrocycles comprising a structural fragment of 6,7-diamino-2,3-diphenylquinoxaline has been elaborated using Pd-catalyzed amination providing target compounds in yields up to 77%. A series of nine novel N - and N , O -containing macrocyclic ligands differing by the number of donor sites and cavity size has been obtained. These compounds possess well-pronounced fluorescent properties with emission maxima in a blue region in aprotic solvents and high quantum yields of fluorescence, while in proton media, fluorescence shifts towards the green region of the spectrum. Using macrocycles 5c and 5e as examples, we have shown that such compounds can serve as dual-channel (colorimetric and fluorimetric) pH indicators in water media, with pH transition point and response being dependent on the macrocycle structure due to different sequences of protonation steps.

In the present review, we discuss recent progress in the field of C-Z bond formation reactions (Z = S, Se, Te) catalyzed by transition metals. Two complementary methodologies are considered─catalytic cross-coupling reactions and catalytic addition reactions. The development of advanced catalytic systems is aimed at improved catalyst efficiency, reduced catalyst loading, better cost efficiency, environmental concerns, and higher selectivity and yields. The important rise of research efforts in sustainability and green chemistry areas is critically assessed. The paramount role of mechanistic studies in the development of a new generation of catalytic systems is addressed, and the key achievements, problems, and challenges are summarized for this field.

A convenient Pd- and phosphine-free protocol for assembling internal alkynes from tertiary propargyl alcohols and (het)aryl halides has been developed. The proposed tandem approach includes the base-promoted retro-Favorskii fragmentation followed by Cu-catalyzed C(sp)-C(sp 2 ) cross-coupling. The use of inexpensive reagents ( e.g. a catalyst, additives, a base, and a solvent) and good functional group tolerance make the procedure practical and cost-effective. The synthetic utility of the method was demonstrated by a smooth alkynylation of vinyl iodides derived from natural steroidal hormones.

Ru(II) complexes with polypyridyl ligands play a central role in the development of photocatalytic organic reactions. This work is aimed at the structural modification of such complexes to increase their photocatalytic efficiency and adapt them for the preparation of reusable photocatalytic systems. Nine [Ru(phen)(bpy) 2 ] 2+ -type complexes (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) (Ru-Pcat) bearing the P(O)(OEt) 2 substituent attached to the phen core directly or through a 1,4-phenylene linker were synthesized and characterized by spectroscopic and electrochemical techniques. The coordination mode of phen ligands was confirmed by single crystal X-ray analysis. The (spectro)electrochemical data show that the first electron transfer in Ru-Pcat takes place on the phen ligand. The emission maxima and quantum yields are strongly affected by the substitution pattern, reaching the far-red region (697 nm) for Ru-3,8P2. The singlet oxygen quantum yields of Ru-Pcat were evaluated using the chemical trapping method. Finally, the photocatalytic performance of Ru-Pcat in the oxidation of sulfides with molecular oxygen was investigated. Both dialkyl and alkyl aryl sulfides were quantitatively transformed into sulfoxides under irradiation with a blue LED in the acetonitrile-water mixture (10 : 1) using a low loading of 0.005-0.05 mol% Ru(II) photocatalysts. To rationalize the effect of phosphonate substituents on the photocatalytic efficiency, comparative kinetic studies of (1) 4-nitrothioanisole oxidation proceeding predominantly via the electron transfer pathway and (2) oxidation of dibutyl sulfide wherein singlet oxygen serves as an oxidant have been performed. It was demonstrated that complexes with the P(O)(OEt) 2 substituent at positions 4 and 7 outperform the benchmark photocatalyst Ru-(bpy)3 and the parent complex Ru-phen in the reactions proceeding through electron transfer (reductive quenching photocatalytic cycle). The TON in the oxidation of 4-methoxythioanisole was found to be as high as 1 000 000 that is, to our knowledge, the highest among previously reported photocatalysts. In contrast, upon separating the P(O)(OEt) 2 group and the phen core with the 1,4-phenylene linker, singlet oxygen quantum yields significantly increase that favors reactions proceeding through energy transfer (the oxidation of dibutyl sulfide in our case). Thus, both series of Ru(II) complexes prepared in this work are promising for the improvement of known photocatalytic reactions and the development of new transformations.

An efficient domino approach to assemble benzoxazoles and anthranilamides bearing dithiocarbamate moieties has been developed. The proposed route represents a Cu-catalyzed three-component reaction between readily available 5-iodo-1,2,3-triazoles, amines, and CS 2 . The cascade transformation is based on a denitrogenative coupling of in situ formed dithiocarbamic acids with diazo intermediates, generated via annulation-triggered triazole ring-opening. This method is applicable to nucleophilic secondary amines and features good functional group compatibility.

The ability of [1,2,3]triazolobenzoxazinones to act as a source of "hidden" diazo group was discovered. These diazo precursors can be easily prepared by the intramolecular cyclization of 2-(5-iodo-1,2,3-triazolyl)benzoic acids. The Cu-catalyzed capture of the hidden diazo group allows for further functionalization through the denitrogenative pathway. The transformations proceed via the formation of either diazoimine or diazoamide intermediates. Novel routes to various anthranilamides as well as thiolated benzoxazinones were developed using the one-pot cyclization/diazo capture procedure.

The simple synthetic procedure for preparation of α-aryl-α-diazophosphonates via a diazo transfer reaction is proposed. Benzylphosphonates reacted with tosyl azide (TsN 3 ) in the presence of potassium tert -butoxide (KO t Bu) to afford diazophosphonates in a yield up to 79%. The proposed method is general. The reaction uses easily available starting materials, tolerates various functional groups, and may be applied for multi-gram scale synthesis.

A straightforward domino approach to assemble benzoxazole-derived sulfonamides has been developed. The method is based on annulation-induced in situ generation of diazo compounds from readily available 2-(5-iodo-1,2,3-triazolyl)phenols, followed by metal-free denitrogenative transformation upon the action of 1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide) (DABSO) and amines. The protocol is operationally simple and features a broad substrate scope, furnishing a library of target compounds in generally good yields.

N -heteroaryl substituted adamantane-containing amines are of substantial interest for their perspective antiviral and psychotherapeutic activities. Chlorine atom at alpha-position of N -heterocycles has been substituted by the amino group using convenient nucleophilic substitution reactions with a series of adamantylalkylamines. The prototropic equilibrium in these compounds was studied using NMR spectroscopy. The introduction of the second amino substituent in 4-amino-6-chloropyrimidine, 2-amino-chloropyrazine, and 1-amino-3-chloroisoquinoline was achieved using Pd(0) catalysis.

Metal-catalyzed (Cu, Ag, Au) reactions of alkynylphosphonates with 1-(2-aminophenyl)-2,2,2-trifluoroethan-1-ones were developed. Terminal alkyne diethyl ethynylphosphonate reacted with ketones to give different products depending on the catalyst used. With a CuI/PPh 3 catalytic system, the formation of CF 3 -containing indoline derivatives was observed with good yields. The use of AgSbF 6 as a catalyst led to quinoline derivatives in high yields. The less reactive 2-substituted ethynylphosphonates required gold complexes as catalysts to provide the corresponding 2-aryl(alkyl) substituted 4-(trifluoromethyl)quinolin-3-ylphosphonates with good yields.

Colchicine, the main alkaloid of Colchicum autumnale , is one of the most famous natural molecules. Although colchicine belongs to the oldest drugs (in use since 1500 BC), its pharmacological potential as a lead structure is not yet fully exploited. This review is devoted to the synthesis and structure-activity relationships (SAR) of colchicine alkaloids and their analogues with modified A, B, and C rings, as well as hybrid compounds derived from colchicinoids including prodrugs, conjugates, and delivery systems. The systematization of a vast amount of information presented to date will create a paradigm for future studies of colchicinoids for neoplastic and various other diseases.

An important strategy for the efficient generation of diversity in molecular structures is the utilization of common starting materials in chemodivergent transformations. The most studied solutions for switching the chemoselectivity rely on the catalyst, ligand, additive, solvent, temperature, time, pressure, pH and even small modifications in the substrate. In this review article several processes have been selected such as inter- and intramolecular cyclizations, including carba-, oxa-, thia- and oxazacyclizations promoted mainly by Brønsted or Lewis acids, transition metals and organocatalysts, as well as radical reactions. Catalyst-controlled intra- and intermolecular cyclizations are mainly described to give five- and six-membered rings. Cycloaddition reactions involving (2+2), (3+2), (3+3), (4+1), (4+2), (5+2), (6+2) and (7+2) processes are useful reactions for the synthesis of cyclic systems using organocatalysts, metal catalysts and Lewis acid-controlled processes. Addition reactions mainly of carba- and heteronucleophiles to unsaturated conjugated substrates can give different adducts via metal catalyst-, Lewis acid- and solvent-dependent processes. Carbonylation reactions of amines and phenols are carried out via ligand-controlled transition metal-catalyzed multicomponent processes. Ring-opening reactions starting mainly from cyclopropanols, cyclopropenols and epoxides or aziridines are applied to the synthesis of acyclic versus cyclic products under catalyst-control mainly by Lewis acids. Chemodivergent reduction reactions are performed using dissolving metals, sodium borohydride or hydrogen transfer conditions under solvent control. Oxidation reactions include molecular oxygen under solvent control or using different dioxiranes, as well as chemodivergent palladium catalyzed cross-coupling reactions using boronic acids are applied to aromatic and allenic compounds. Other chemodivergent reactions such as alkylations and allylations under transition metal catalysis, dimerization of acetylenes, bromination of benzylic substrates, and A 3 -couplings are performed via catalyst- or reaction condition-dependent processes.

An efficient cascade approach to thiosubstituted benzoxazoles has been developed. The transformation starts with in situ generation of a diazo compound via annulation-triggered electrocyclic opening of the 1,2,3-triazole ring. The subsequent Cu-catalyzed trapping of diazo intermediates by various thiols affords the desired heterocycles in generally good yields of up to 91%. The protocol features very good functional group tolerance and is applicable to substrates with different electronic properties.

An efficient direct approach to triazole-fused sultams has been developed. The key step of the proposed strategy is base-mediated cyclization of sulfonamide-tethered 5-iodo-1,2,3-triazoles which are readily available via an improved protocol for Cu-catalyzed 1,3-dipolar cycloaddition. The annulation of the sultam fragment to the triazole ring proceeds smoothly under transition-metal-free conditions in the presence of Cs 2 CO 3 in dioxane at 100 °C and affords fused heterocycles in high yields up to 99%. The favorability of an S N Ar-like mechanism for the cyclization was supported by DFT calculations. The applicability of the developed procedure to modification of natural compounds was demonstrated by preparation of a deoxycholic acid derivative.

Pd(0)-catalyzed amination was employed for the synthesis of a new family of ( S )-1,1'-bianaphthalene-2,2'-diamine derivatives possessing additional chiral and fluorophore substituents. The compounds thus obtained were tested as potential detectors of seven amino alcohols, and some of them were found to be able to recognize individual enantiomers of certain amino alcohols by specific changes of their emission spectra in the presence of these analytes. A pronounced dependence of the detecting abilities on the nature of the substituents in the ( S )-BINAM derivatives was observed.

The comparison of the possibilities of Pd- and Cu-catalyzed amination reactions using fluorine-containing aryl bromides and iodides with oxadiamines to produce their N,N' -diaryl derivatives was carried out. The dependence of the reactivity of the aryl halides on the nature of the substituents and halogen atoms as well as on the structure of oxadiamines was investigated. It was found that the copper-catalyzed reactions were somewhat comparable with the palladium-mediated processes in the majority of cases, especially in the reactions with para -fluorine- and para -(trifluoromethyl)-substituted aryl halides, although the necessity to use aryl iodides in the Cu(I)-catalyzed amination was obvious. Pd catalysis was found inevitable for the successful amination of more sterically hindered ortho -(trifluoromethyl)aryl bromides.

Trifluorodiazoethane is a widely explored trifluoroethylating reagent, which is suitable for the preparation of a large number of fluorine-containing organic molecules. Nevertheless, CF 3 CHN 2 has some disadvantages, such as volatility, storage instability, toxicity, and explosiveness. We report the application of trifluoroacetaldehyde N -tosylhydrazone as a CF 3 CHN 2 precursor capable of generating in situ trifluorodiazoethane under mild basic conditions. Copper-catalyzed P-H, O-H, S-H, and C-H insertion reactions of trifluoroacetaldehyde N -tosylhydrazone revealed its wide applicability in the synthesis of trifluoroethyl-containing substances.

Metal-catalyzed regiodivergent reactions allow control over regioselectivity in the synthesis of a wide range of organic products. Starting from the same material, it is possible to prepare different regioisomers just by appropriately choosing the catalyst or by modifying the reaction conditions. Therefore, these regiodivergent methodologies should be included as the key factor in the concept of efficiency and atom economy in synthetic organic chemistry. The synthetic potential of this subject has been demonstrated mainly in addition reactions to unsaturated carbon-carbon bonds, allylic and propargylic nucleophilic substitutions, C-H activation reactions, cross-couplings, and intramolecular or intermolecular cyclizations. This review article overviews the development and rationalization of regiodivergence in these fundamental reactions in the last 15 years.

Eight 1,10-phenanthrolines bearing one or two 2-(1-adamantyloxy)ethylamino substituents attached to different positions of the heterocyclic core were prepared according to S N Ar or palladium-catalyzed amination reactions. Their reaction with cis-Ru(bpy) 2 Cl 2 (bpy=2,2'-bipyridine) was investigated and Ru(bpy) 2 (L)(PF 6 ) 2 (phen=1,10-phenanthroline) (L=amino-substituted 1,10-phenanthroline) complexes were obtained in good yields. The electronic structure and emissive properties of these complexes are strongly dependent on the position of the amino substituent in the heterocycle. Emission bands of the complexes bearing 2- and 4-substituted 1,10-phenanthroline ligands are red-shifted (up to 56 nm) and less intense compared to that of the parent [Ru(phen)(bpy) 2 ](PF 6 ) 2 . In contrast, the introduction of the substituent in 3- or 5-position of 1,10-phenanthroline ring induces only small decrease of luminescence and the brightness of the complex with the 3-substituted ligand is comparable to that of the parent complex., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Chemoselective palladium-catalyzed arylation of polyamines with 6-bromoquinoline has been explored to prepare chelators for the detection of metal cations in aqueous media. The introduction of a single aromatic moiety into non-protected polyamine molecules was achieved using the commercially available Pd(dba)2/BINAP precatalyst to afford nitrogen chelators, in which the aromatic signalling unit is directly attached to the polyamine residue. Water-soluble receptors were then synthesized using N-alkylation of these polyamines by hydrophilic coordinating residues. By combining rich photophysical properties of the 6-aminoquinoline unit with a high coordination affinity of chelating polyamines and a hydrophilic character of carboxamido-substituted phosphonic acid diesters in a single molecular device, we synthesized chemosensor 5 for selective double-channel (UV-vis and fluorescence spectroscopies) detection of CuII ions in aqueous media at physiological levels. This receptor is suitable for the analysis of drinking water and fabrication of paper test strips for the naked-eye detection of CuII ions under UV-light. By increasing the number of donor sites we also obtained chemosensor 6 which is efficient for the detection of HgII ions. Moreover, chemosensor 6 is also suitable for multiple detection of metal ions because it chelates not only HgII but also CuII and ZnII ions displaying different responses of emission in the presence of these three cations.

The Markovnikov rule, known to every student of organic chemistry, was formulated 150 years ago, in 1869. During its long history (almost as long as the history of organic chemistry itself), attitudes towards this famous statement of chemical reactivity have evolved from indifference up to the 1930s, through common acceptance as a useful educational paradigm with marginal use in research up to the 1990s, to its vigorous relaunch as an important designation of regioselectivity in the last few decades. The unexpected new popularity of the classical rule is accounted for by the rapid expansion in catalytic addition reactions and their critical importance as highly effective atom-economical, regioselective methods in modern organic synthesis. A historical outline of the life and achievements of Vladimir Markovnikov is included to reveal the very wide scope of his interests as well as his prophetic predictions on structure, reactivity, selectivity, stereochemistry, and other key issues of organic chemistry., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Base-mediated cyclization of (5-iodo-1,2,3-triazolyl)phenols was proposed as a new synthetic strategy for the in situ generation of diazoimines via electrocyclic ring opening of the fused heterocycle. Cu-catalyzed amination of the intermediate diazoalkanes was employed to develop an efficient cascade approach to functionalized benzoxazoles.

This review covers diastereo- and enantiodivergent catalyzed reactions in acyclic and cyclic systems using metal complexes or organocatalysts. Among them, nucleophilic addition to carbon-carbon and carbon-nitrogen double bonds, α-functionalization of carbonyl compounds, allylic substitutions, and ring opening of oxiranes and aziridines are considered. The diastereodivergent synthesis of alkenes from alkynes is also included. Finally, stereodivergent intramolecular and intermolecular cycloadditions and other cyclizations are also reported.

The arylation of mono-, di- and tetra- meso -bromophenyl-substituted porphyrins with the heteroarenes containing "acidic" C-H bonds, such as benzoxazole, benzothiazole and N -methylimidazole was studied in the presence of three alternative catalytic systems: Pd(dba) 2 /DavePhos/Cs 2 CO 3 , Pd(PPh 3 ) 4 /PivOH/K 2 CO 3 and Pd(OAc) 2 /Cu(OAc) 2 /PPh 3 /K 2 CO 3 . The first catalytic system was found to be successful in the reaction with benzoxazole, the second one was less efficient for our purpose, while the third system proved to be most versatile and afforded corresponding mono-, di-, tri- and even tetraarylated derivatives of porphyrins.

Cu- and Pd-catalyzed arylation of aminocholanes has been described for the first time. While this Cu-catalyzed protocol provides high yields in reactions of aminocholanes with iodoarenes, Pd catalysis was found to be preferable for the reactions of aminocholanes with dichloroanthraquinones. UV-vis titration of bis(cholanylamino)anthraquinones with a series of cations demonstrated their high binding affinity to Cu 2+ , Al 3+ , and Cr 3+ .

5-Aryl-substituted pyrazol-3-ylphosphonates have been conveniently synthesized by 1,3-dipolar cycloaddition of 1-formamidovinylphosphonates and aryldiazomethanes under K 2 CO 3 /MeOH conditions at room temperature. These pyrazoles are formed in one pot via spontaneous elimination of formamide. Basic conditions prevent competitive formation of cyclopropylphosphonates. 3-Aryl substituted pyrazol-5-carboxylates can be synthesized by the same methodology from 1-arylvinylphosphonates and ethyl diazoacetate, although a stronger base NaH is necessary to ensure the success of the aromatization stage with the elimination of the diethoxylphosphoryl moiety.

Carbonylmetallates, [M(CO)(n)L](-), anionic transition-metal carbonyl complexes, represent a large family of metal-centered nucleophiles, and studying carbonylmetallates allows us to understand the differences in the behavior of the metal-centered complexes versus heteroatom-based nucleophiles. The mechanisms of carbonylmetallate reactions with aryl- and alkenyl halides have been examined by employing radical and, especially, carbanion trapping techniques. Carbonylmetallates show a marked preference for halogenophilic attack, and nucleophilic substitution with carbonylmetallates is often not a direct process, but proceeds through the initial attack at halogen with subsequent coupling of carbanion and HalM(CO)(n)L intermediates. Factors governing the competition between the halogenophilic and more common "carbophilic" reaction pathways, as well as the means of predicting the actual course of reaction are discussed. The review also considers other aspects of carbonylmetallate reactivity, including ion-pairing effects, radical-mediated nucleophilic substitution pathways, and the carbonylmetallate nucleophilicity scale in the reactions with π-electrophiles., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A series of ditopic macrocyclic receptors with variable cavity sizes, containing nitrogen or mixed (nitrogen-oxygen) donor sites and an externally directed 1,10-phenanthroline fragment, were prepared by means of a palladium-catalyzed amination reaction. A ditopic mixed NO-ligand (4 a) was coordinated to [Ru(bpy) 2 ] 2+ (bpy=2,2'-bipyridine) to prepare a luminescent and chromogenic complex, [Ru(bpy) 2 (4 a)][PF] 2 , which provided the selective dual-channel detection of Cu II ions., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The Cu(I)-catalyzed N,N'-diarylation of natural diamines and polyamines such as putrescine, cadaverine, spermine, spermidine and their homologues is described. Aryl iodides bearing electron-donating and electron-withdrawing groups have been employed in the study. The CuI/2-(isobutyryl)cyclohexanone/DMF catalytic system has found to be more efficient in the diarylation of diamines and spermine while the CuI/L-proline/EtCN system proved to be preferable for the diarylation of other tri- and tetraamines like spermidine, norspermidine and norspermine.

It was found out that block copolymers of polystyrene and poly(4-vinylpyridine) with comparable lengths of blocks could be dissolved in a high-pressure reactor containing water phase saturated with carbon dioxide under high pressure at room temperature. This rather effective dissolution occurs due to a protonation of P4VP nitrogen-containing groups together with a plasticization of the polymer material to be dissolved by a compressed dense CO 2 being contained in the autoclave. The selected block copolymers form rather monodispersed micelles with well-defined and reproducible spherical geometry. They apparently have a hydrophobic polystyrene core and a polycationic poly-4-vinylpyridine corona. The obtained micelles were characterized by various techniques such as DLS, AFM, TEM, and SEM. Further, it was revealed that the corona of such micelles could be decorated with Pd nanoparticles having the diameter around 3 nm.

α,α-Difluoro-β-ketophosphonated derivatives of tetraazamacrocycles were synthesized and found to be potential inhibitors of protein tyrosine phosphatases. N-Substituted conjugates of cyclam and cyclen with bioisosteric phosphonate groups displayed good activities toward T-cell protein tyrosine phosphatase with IC50 values in the micromolar to nanomolar range and showed selectivity over PTP1B, CD45, SHP2, and PTPβ. Kinetic studies indicated that the inhibitors can occupy the region of the active site of TC-PTP. This study demonstrates a new approach which employs tetraazamacrocycles as a molecular platform for designing inhibitors of protein tyrosine phosphatases.

Cu-catalyzed Pd-free Sonogashira coupling has been proposed as a straightforward and convenient route to valuable steroidal enynes. A biligand catalyst system based on Ph3P and TMEDA has been designed. The protocol was utilized for the efficient coupling of iodosteroids with diverse terminal alkynes and 1-trimethylsilylalkynes. A possible role of an auxiliary ligand as a phase-transfer catalyst for a sparingly soluble inorganic base (K2CO3) was revealed.

A series of conformationally flexible furan-derived allocolchicinoids was prepared from commercially available colchicine in good to excellent yields using a three-step reaction sequence. Cytotoxicity studies indicated the potent activity of two compounds against human epithelial and lymphoid cell lines (AsPC-1, HEK293, and Jurkat) as well as against Wnt-1 related murine epithelial cell line W1308. The results of in vitro experiments demonstrated that the major effect of these compounds was the induction of cell cycle arrest in the G2/M phase as a direct consequence of effective tubulin binding. In vivo testing of the most potent furanoallocolchicinoid 10c using C57BL/6 mice inoculated with Wnt-1 tumor cells indicated significant inhibition of the tumor growth.

A unique Ni-catalyzed transformation is reported for the one-pot highly selective synthesis of previously unknown monoseleno-substituted 1,3-dienes starting from easily available terminal alkynes and benzeneselenol. The combination of a readily available catalyst precursor, Ni(acac)2, and an appropriately tuned phosphine ligand, PPh2Cy, resulted in the exclusive assembly of the s-gauche diene skeleton via the selective formation of C-C and C-Se bonds. The unusual diene products were stable under regular experimental conditions, and the products maintained the s-gauche geometry both in the solid state and in solution, as confirmed by X-ray analysis and NMR spectroscopy. Thorough mechanistic studies using ESI-MS revealed the key Ni-containing species involved in the reaction.

The paper provides the first example of formal nucleophilic substitution by the halogenophilic pathway in Cr(CO)3 complexes of haloarenes with metal carbonyl anions. All metal carbonyl anions examined attack [(η(6)-iodobenzene)Cr(CO)3] at halogen, which is shown by aryl carbanion scavenging with t-BuOH. The reaction with K[CpFe(CO)2] gives only the dehalogenated arene, but the reaction with K[Cp*Fe(CO)2] (Cp* = η(5)-C5Me5) results in nucleophilic substitution to give [(η(6)-C6H5FeCp*(CO)2)Cr(CO)3]. Reaction with Na[Re(CO)5] quantitatively gives the iodo(acyl)rhenate anion Na[(η(6)-C6H5C(O)ReI(CO)4)Cr(CO)3] and in the case of K[Mn(CO)5] a mixture of σ-aryl complexes [(η(6)-C6H5Mn(CO)5)Cr(CO)3] and K[(η(6)-C6H5Mn(CO)4I)Cr(CO)3]. An analogous rhenium complex Na[(η(6)-C6H5Re(CO)4I)Cr(CO)3] is formed from the initial iodo(acyl)rhenate upon prolonged standing at 20 °C, and its structure (in the form of [NEt4](+) salt) is established by X-ray diffraction analysis. The reaction of [(η(6)-chlorobenzene)Cr(CO)3] with K[CpFe(CO)2], in contrast, proceeds by the common S(N)2Ar mechanism.

Copper-catalyzed 1,3-dipolar cycloaddition has been employed in the reaction of steroidal azides with various terminal alkynes. A number of novel 1,2,3-triazolyl derivatives of pregnane, androstane and D-homoandrostane were obtained in high yield (70-98%). The developed synthetic protocols allowed us to attach the triazolyl moiety to both the side chain and the steroidal backbone directly, despite the steric hindrance exerted by the polycyclic system. The presence of Cu(II) was shown to evoke d-homo rearrangement under mild conditions. A rational choice of the copper precatalyst permitted us to carry out the "click" reaction either along with tandem d-homo rearrangement or in the absence of this process. The tendency of 16-heterosubstituted steroids to undergo D-homo rearrangement under Cu(II) catalysis was studied.