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We report the extension of the common β-diketimine proligand class, RArnacnacH (HC(RCNAr)2H), where R is an alkyl group such as Et or iPr, plus Ph, and Ar is a sterically demanding aryl substituent such as Dip = 2,6-diispropylphenyl, Dep = 2,6-diethylphenyl, Mes = 2,4,6-trimethylphenyl or mesityl, Xyl = 2,6-dimethylphenyl, via one-pot condensation procedures. When a condensation reaction is carried out using the chemical dehydrating agent PPSE (polyphosphoric acid trimethylsilylester), β-diketiminate phosphorus(V) products such as (iPrMesnacnac)PO2 can also be obtained, which can be converted to the respective proligand iPrMesnacnacH via alkaline hydrolysis. The RArnacnacH proligands can be converted to their alkali metal complexes with common methods and we have found that deprotonation of iPrDipnacnacH is significantly more sluggish than that of related β-diketimines with smaller backbone alkyl groups. The basicity of the RArnacnac− anions can play a role in the success of their salt metathesis chemistry and we have prepared and structurally characterised the EtDipnacnac-derived silicon(II) compounds (EtDipnacnac)SiBr and (EtDipnacnac')Si, where EtDipnacnac' is the deprotonated variant MeCHC(NDip)CHC(NDip)Et. [ABSTRACT FROM AUTHOR]

Two new heteroleptic indium aminothiolate compounds [InClSC2H4N(Me)SC2H4]3[1] and [InSC2H4N(Me)SC2H4(C8H5F3NO)] [2] were synthesized by in situ salt metathesis reaction involving indium trichloride, aminothiol, and N,O-β-heteroarylalkenol ligands. The complexes were subsequently purified and thoroughly characterized by nuclear magnetic resonance (NMR) analysis, elemental studies, mass spectroscopy, and X-ray diffraction single crystal analysis that showed a trigonal bipyramidal coordination of In(III) in both complexes. Thermogravimetric analysis of [1] revealed a multistep decomposition pathway and the formation of In2S3 at 350 °C, which differed from the pattern of [2] due to the lower thermal stability of [1]. Compound [2] exhibited a three-step decomposition process, resulting in the formation of In2S3 at 300 °C. The Chemical Vapor Deposition (CVD) experiment involving compound [2] was conducted on the FTO substrate, resulting in the production of singular-phase In2S3 deposits. A comprehensive characterization of these deposits, including crystal structure analysis via X-ray diffraction (XRD), and surface topography examination through scanning electron microscopy (SEM) has been completed. The presence of In–S units was also supported by the Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDS) of the as-deposited films. Moreover, the electronic structure and thermal properties of compound [2] were investigated through DFT calculations. Electron density localization analysis revealed that the highest occupied molecular orbital (HOMO) exhibited dense concentration at the aminothiolate moiety of the complex, while the lowest unoccupied molecular orbital (LUMO) predominantly resided at the N,O-β-heteroarylalkenolate ligand. Furthermore, our computational investigation has validated the formation of indium sulfide by elucidating an intermediate state, effectively identified through EI-MS analysis, as one of the plausible pathways for obtaining In2S3. This intermediate state comprises the aminothiolate ligand (LNS) coordinated with indium metal. [ABSTRACT FROM AUTHOR]

Cyclohepta[b]indoles, prevalent in natural products and pharmaceuticals, are conventionally accessed via metal or Lewis acid‐mediated cycloadditions with prefunctionalized substrates. Our study introduces an innovative sequential catalytic assembly for synthesizing cyclohepta[b]indoles from readily available isatin derivatives. The process involves three catalytic sequences: ring‐closing metathesis, catalytic hydrogenation, and acid‐catalyzed ring expansion. The RCM of 2,2‐dialkene‐3‐oxindoles, formed by butenyl Grignard addition to 3‐allyl‐3‐hydroxy‐2‐oxindoles, yields versatile spirocyclohexene‐3‐oxindole derivatives. These derivatives undergo further transformations, including dibromination, dihydroxylation, epoxidation, Wacker oxidation at the double bond. Hydrogenation of spirocyclohexene‐3‐oxindole yields spirocyclohexane‐3‐oxindoles. Their subsequent acid‐catalyzed ring expansion/aromatization, dependent on the acid catalyst, results in either cyclohepta[b]indoles or cyclohepta[b]indole‐indoline conjugates, adding a unique synthetic dimension. The utility of this methodology is exemplified through the synthesis of an A‐FABP inhibitor, showcasing its potential in pharmaceutical applications. [ABSTRACT FROM AUTHOR]

Aigialomycin D, a 14-membered benzannulated macrolactone, was synthesized in a simple, efficient and stereoselective approach using inexpensive and commonly accessible starting materials. The main steps in this convergent synthesis are Corey-Fuchs reaction, Yamaguchi esterification and ring closing metathesis (RCM). [ABSTRACT FROM AUTHOR]

A unified approach to access the naturally occurring cyclic tetrapeptide JM‐47 and some of its structural variants from a common macrocyclic scaffold has been developed. The key reactions involved a difficult macrocyclization to access the scaffold, and its late‐stage diversification by cross‐metathesis to access the natural product as well as analogues. The synthesis proceeded in good overall yield and high stereochemical integrity. It also confirms the structure and configuration assigned to JM‐47. [ABSTRACT FROM AUTHOR]

Among mechanically interlocked supramolecular systems with cyclodextrins (CDs), successful examples of CD‐based catenanes are limited compared to a number of CD rotaxanes owing to the synthetic difficulties. We herein demonstrate an efficient synthesis of a CD‐based catenane using a meso‐arylporphyrin (Por) platform. Using Por modified with two olefin‐terminated oxyethylene chains at the cis‐meso‐positions, an interlocked Por‐CD catenane was synthesized via olefin metathesis in the presence of per‐O‐methylated β‐CD (TMe‐β‐CD) in water. The novel Por‐CD catenane was obtained in 30 % isolated yield, which was characterized by MALDI‐TOF mass and NMR spectroscopies. In the latter part, we demonstrate determination of the binding constants between TMe‐β‐CD and meso‐(4‐sulfonatophenyl)porphyrin using Por‐CD catenane, 2,6‐di‐O‐methyl‐β‐CD (DMe‐β‐CD), and 13C‐labeled TMe‐β‐CD (13C‐TMe‐β‐CD). The host‐guest exchange reaction from the Por‐CD catenane/DMe‐β‐CD to the Por‐CD catenane/TMe‐β‐CD complexes was directly monitored through 1D HMQC spectroscopy. The ratio of these complexes revealed the difference in the binding affinities of DMe‐β‐CD and TMe‐β‐CD to Por. The stable 1 : 2 inclusion complex between meso‐tetrakis(4‐sulfonatophenyl)porphyrin (TPPS) and TMe‐β‐CD has been well‐studied for many years. This study is the first to determine the respective binding constants, K1 and K2, using the model system, to be 3.0×107 M−1 and 3.4×107 M−1, respectively. [ABSTRACT FROM AUTHOR]

The salt metathesis of a boryl-ethynyl lithium salt {[(HCDipN)2]B-CC-Li} with a monochlorosilylene [LSi(:)Cl; L = PhC(NtBu)2] produced an isolable boryl-ethynyl silylene {1; [(HCDipN)2]B–C≡C–Si(L)}. The Si(II) center in 1 possesses a nonbonding lone pair and forms a covalent bond with the ethynyl group. The characterization of 1 was carried out by multinuclear NMR spectroscopy, single-crystal X-ray structure analysis and DFT calculations. Additionally, a reactivity study of 1 was conducted towards oxygen-containing and aryl C–F substrates. [ABSTRACT FROM AUTHOR]

A biphenyl derivative in which two benzene rings are strapped with two chains is prepared. The synthesized product shows molecular asymmetry, which was confirmed by HPLC analysis with chiral column and named as winding vine‐shaped biphenyl. The synthesis of such vine shaped molecule was performed by ring‐closing metathesis or alternatively by annulation with nosylated ethylenediamine. The structure of the obtained product was confirmed by X‐ray crystallographic analysis. The absolute configuration of the molecular asymmetry was assigned after leading to the corresponding camphor sulfonamide through denosylation and re‐amidation process. [ABSTRACT FROM AUTHOR]

A series of sulfates (S) and hydrogen sulfates (HS) containing tetramethylphosphonium (TMP), tetraethylphosphonium (TEP) and tetrabutylphosphonium (TBP) cations have been prepared from the respective bromides using ion metathesis reactions. The products were identified using spectroscopic methods (FTIR, NMR), as well as powder and single-crystal X-ray diffraction. All the hydrogen sulfates contain HSO4− anions associated via hydrogen bonds, forming either a (HSO4)22− dimer (as for TEPHS and TBPHS) or a zigzag chain, (HSO4)nn− (for TMPHS). Such associated anions are surrounded by four TMP and TEP or three TBP cations per one sulfur atom. The reported sulfates reveal much larger separation of the anions, while the double anion charge implies slightly closer distances between the counterion centers and the tendency for forming hydrates. TBPS and TBPHS melt close to 100 °C, at a much lower temperature than the salts containing smaller cations, while thermal decomposition of all these salts begins within ca. 300–400 °C. A mixed-anion salt, [(C4H9)4P]4[SO4][HSO4]2, is formed in a molten equimolar mixture of TBPS and TBPHS. The obtained salt is composed of separated SO42− and (HSO4)22− anions rather than the (SO4⋯HSO4)3− mixed-anion dimer. [ABSTRACT FROM AUTHOR]

Isomerization Metathesis (ISOMET) reaction is an emerging tool for "open loop" chemical recycling of polyethylene to propylene. Novel, latent N‐Alkyl substituted Cyclic(Alkyl)(Amino)Carbene (CAAC)–ruthenium catalysts (5a‐Ru, 3b‐Ru – 6c‐Ru) are developed rendering "inverted" chemical structure while showing enhanced ISOMET activity in combination with (RuHCl)(CO)(PPh3)3 (RuH) double bond isomerization co‐catalyst. Systematic investigations reveal that the steric hindrance of the substituents on nitrogen and carbon atom adjacent to carbene moiety in the CAAC ligand have significantly improved the catalytic activity and robustness. In contrast to the NHC‐Ru and CAAC‐Ru catalyst systems known so far, these systems show higher isomerization metathesis (ISOMET) activity (TON: 7400) on the model compound 1‐octadecene at as low as 3.0 bar optimized pressure, using technical grade (3.0) ethylene. The propylene content formed in the gas phase can reach up to 20% by volume. [ABSTRACT FROM AUTHOR]

A Grubbs‐type ruthenium complex bearing a tridentate anionic bisfluoroalkoxy‐carbene was synthesised and fully characterised. Under standard conditions, it proved to be inactive in olefin metathesis reactions, but the addition of HCl triggers its activity and allows the synthesis of a series of cyclic olefins and ethers as well as a stereoregular polynorbornene with an unexpectedly high content of trans‐configured double bonds, as found in commercially available polynorbornene (Norsorex®). Detailed structural studies and DFT calculations showed that the complex enters the catalytic cycle, but instead of performing a full turnover, it is caught as a stable intermediate that does not undergo further reactions. The addition of HCl causes dissociation of the fluoroalkoxy units, resulting in a compound that behaves similarly to standard Grubbs‐type complexes. To further understand this phenomenon, the corresponding Hoveyda‐Grubbs complex was also obtained and studied in detail; due to the absence of the phosphine ligand, its behaviour was different from that of its Grubbs‐type counterpart. [ABSTRACT FROM AUTHOR]

The first total synthesis of the Euphorbia diterpenoid pepluacetal is disclosed in both racemic and chiral fashions. The synthesis strategically relies on a photo‐induced Wolff rearrangement/lactonization cascade (WRLC) reaction to access the cyclobutane moiety, a ring‐closing metathesis/cyclopropanation sequence to rapidly forge the 7–3 bicyclic system, and a late‐stage Rh‐catalyzed transannular carbenoid insertion to C(sp3)−H bond followed by a Baeyer–Villiger oxidation and ring‐opening manipulations to install the side chain. The synthetic route demonstrates excellent stereochemical control on the non‐classical concave‐face bond formation, remote traceless stereochemical relay and high scalability to provide 20 mg of (+)‐pepluacetal. [ABSTRACT FROM AUTHOR]

The first total synthesis of the Euphorbia diterpenoid pepluacetal is disclosed in both racemic and chiral fashions. The synthesis strategically relies on a photo‐induced Wolff rearrangement/lactonization cascade (WRLC) reaction to access the cyclobutane moiety, a ring‐closing metathesis/cyclopropanation sequence to rapidly forge the 7–3 bicyclic system, and a late‐stage Rh‐catalyzed transannular carbenoid insertion to C(sp3)−H bond followed by a Baeyer–Villiger oxidation and ring‐opening manipulations to install the side chain. The synthetic route demonstrates excellent stereochemical control on the non‐classical concave‐face bond formation, remote traceless stereochemical relay and high scalability to provide 20 mg of (+)‐pepluacetal. [ABSTRACT FROM AUTHOR]

Transition‐metal (TM) catalyzed reaction of gem‐difluorinated cyclopropanes (gem‐DFCPs) has drawn much attention recently. The reaction generally occurs via the activation of the distal C─C bond in gem‐DFCPs by a low‐valent TM through oxidative addition, eventually producing mono‐fluoro olefins as the coupling products. However, achieving regioselective activation of the proximal C─C bond in gem‐DFCPs that overcomes the intrinsic reactivity via TM catalysis remains elusive. Here, a new reaction mode of gem‐DFCPs enabled by high‐valent copper catalysis, which allows exclusive activation of the congested proximal C─C bond is presented. The reaction that achieves fluoroarylation of gem‐DFCPs uses NFSI (N‐fluorobenzenesulfonimide) as electrophilic fluoro reagent and arenes as the C─H nucleophiles, enabling the synthesis of diverse CF3‐containing scaffolds. It is proposed that a high‐valent copper species plays an important role in the regioselective activation of the proximal C─C bond possibly via a σ‐bond metathesis. [ABSTRACT FROM AUTHOR]

Diversity‐oriented synthesis of some novel functionalized azaheterocyclic β‐amino esters with multiple chiral centers from 1,3‐cyclooctadiene‐based β‐amino acids through a stereocontrolled synthetic route has been accomplished. The strategy was based on the creation of some novel unsaturated N‐protected cyclic β‐amino esters from 1,3‐cyclooctadiene. Products were subjected to ring‐opening metathesis (ROM) followed by selective ring‐closing metathesis (RCM). A comparative investigation on the selectivity, regarding the catalysts, yields, conversions, and substrate directing effect on ring‐rearrangement metathesis (RRM) transformation has been accomplished. Importantly, the procedure used in this synthetic process does not affect the configuration of the chiral centers. The pathway takes place across conservation of the configurations of the stereocenters; therefore, the architectural skeleton of the starting cyclooctene‐based β‐amino acids predetermined the structure of the new azaheterocyclic systems. [ABSTRACT FROM AUTHOR]

The tetracyanamidometallates Li4[T(CN2)4] with T=Si, Ge were prepared by solid‐state metathesis (SSM) reactions between TI4 and Li2(CN2). The new compounds Li4[T(CN2)4] are obtained as crystalline phases in high yields and represent the most basic examples of the family of tetracyanamidometallates. The formation of these compounds, via SiI4 and Li2(CN2), is analyzed by means of differential scanning calorimetry (DSC). The [Si(CN2)4]4− ion in the structure of Li4[Si(CN2)4] can be considered an analogue to the [SiO4]4− ion in Li4SiO4. The crystal structures of Li4[T(CN2)4] were solved and refined isotypically on the basis of single‐crystal X‐ray diffraction data in the space group C2/c, and further characterized by infrared and solid‐state NMR techniques. [ABSTRACT FROM AUTHOR]

Research on zinc-ion hybrid supercapacitors has been gaining much attention due to the combination of their high energy and power density. However, the cost of preparation and poor rate performance of porous carbon cathode materials are two major issues limiting their large-scale utilization. In this study, we used nano calcium carbonate as the hard template agent and economical lignin as the carbon source to synthesize lignin-derived porous carbon with high specific surface areas and high mesopore ratios. Through a double decomposition reaction, calcium chloride produced by acid pickling is combined with sodium carbonate to create nano-calcium carbonate, thus enabling the regeneration of nano-calcium carbonate. More importantly, carbon dioxide resulting from the pyrolysis of calcium carbonate causes an internal activation effect on carbon materials, thus causing the formation of micropores and expanding the pore size of some micropores and small mesopores. Through this strategy, the specific surface area of lignin-derived porous carbon is up to 860.5 m² g-1, and the mesopore volume accounts for more than 90% of the total pore volume. The zinc-ion hybrid supercapacitor with lignin-derived porous carbon as the cathode displays an impressive capacity retention rate of 64% when the current density is increased from 0.1 to 20 A g-1. This work provides a green and sustainable route for the development of low-cost, high-rate performance porous carbon materials. [ABSTRACT FROM AUTHOR]

The salt metathesis reaction of dipotassium germacyclopentadienediide with aluminum(III) dichlorides provides either half‐sandwich alumole complexes of germanium(II) or aluminylene germole complexes. Their molecular structure and the delocalized bonding situation, revealed by density functional theory (DFT) calculations, are equally described as isomeric aluminagerma[5]pyramidanes with either the germanium or the aluminum atom in the apical position of the pentagonal pyramid. The product formation and the selectivity of the reaction depends on the third substituent of the aluminum dichloride. Aryl‐substituents favor the formation of alumole complexes and Cp*‐substituents that of the isomeric germole complexes. With amino‐substituents at the aluminum atom mixtures of both isomers are formed and the positional exchange of the two heteroatoms is shown by NMR spectroscopy. The alumole complexes of germanium(II) undergo facile reductive elimination of germanium and form the corresponding alumoles. [ABSTRACT FROM AUTHOR]

This article discusses a new method for synthesizing spirocyclopentene oxindoles, which are found in natural products and biologically active molecules. The authors describe the synthesis process using lithium bis(trimethylsilyl)amide (LiHMDS) and ring closing metathesis. The yields of the desired compounds ranged from 55% to 88%, with some side products observed in certain cases. The authors provide detailed physical and spectroscopic data for each compound synthesized. The article acknowledges the institutions that provided resources and support for the research. [Extracted from the article]

The molecular complexes described herein use main‐group elements or transition metals to control the stoichiometric cleavage of N−H bonds of ammonia (NH3) and/or catalyze chemical and electrochemical NH3 oxidation to dinitrogen (N2). We highlight the phenomenon of coordination‐induced bond weakening and a variety of N−H bond cleavage mechanisms of NH3 including H atom abstraction, inter‐ and intra‐molecular deprotonation reactions, oxidative addition, and σ‐bond metathesis that have been demonstrated with molecular systems. We provide an overview of the molecular complexes reported for the rapidly developing field of NH3 oxidation catalysis to form N2. These systems exhibit several diverse structure types and innovative ligands to support transition metals capable of activating NH3 and mediating a challenging chemical transformation that requires breaking strong N−H bonds and forming an N−N bond en route to N2 formation. [ABSTRACT FROM AUTHOR]

The germylone dimNHCGe (5, dimNHC=diimino N‐heterocyclic carbene) undergoes a [2+2] cycloaddition with isocyanates RNCO (R=4‐tolyl or 3,5‐xylyl) to furnish novel alkyl carboxamido germylenes 7 (R=4‐tolyl) and 8 (R=3,5‐xylyl), featuring a C−C bond between the former carbene carbon and the isocyanate moiety. Heating a mixture of 8 with 4‐tolyl isocyanate to 100 °C results in isocyanate metathesis, demonstrating reversible C−C bond formation on the reduced germanium compound. DFT calculations suggest that this process occurs via the reductive dissociation of isocyanate from 8 that regenerates the parent Ge(0) compound 5. [ABSTRACT FROM AUTHOR]

Cascade metathesis polymerization has been developed as a promising method to synthesize complex but well‐defined polymers from monomers containing multiple reactive functional groups. However, this approach has been limited to the monomers involving simple alkene/alkyne moieties or produced mainly non‐degradable polymers. In this study, we demonstrate a complete cascade ring‐opening/ring‐closing metathesis polymerization (RORCMP) using various tricycloalkenes and two strategies for the efficient degradation. Through rational design of tricycloalkene monomers, the structure and reactivity relationship was explored. For example, tricycloalkenes with trans configuration in the central ring enabled faster and better selective cascade RORCMP than the corresponding cis isomers. Also, a 4‐substituted cyclopentene moiety in the monomers significantly enhanced the overall cascade RORCMP performance, with the maximum turnover number (TON) reaching almost 10,000 and molecular weight up to 170 kg/mol using an amide‐containing monomer. Furthermore, we achieved one‐shot cascade multiple olefin metathesis polymerization using tricycloalkenes and a diacrylate, to produce new highly A,B‐alternating copolymers with full degradability. Lastly, we successfully designed xylose‐based tricycloalkenes to give well‐defined polymers that underwent ultra‐fast and complete degradation under mild conditions. [ABSTRACT FROM AUTHOR]

We have accomplished the first and asymmetric total synthesis of principinol B, a grayanoid possessing an oxabicyclo[3.2.1] architecture. A functionalized 5/7/6/5 tetracyclic intermediate was assembled in a convergent manner by a diastereoselective intermolecular aldol reaction and subsequent carbonyl–olefin metathesis of two enantiomerically enriched fragments. The oxabicyclo[3.2.1] architecture containing a 6,10‐ether bridge was constructed by the Williamson ether synthesis. [ABSTRACT FROM AUTHOR]

Cascade metathesis polymerization has been developed as a promising method to synthesize complex but well‐defined polymers from monomers containing multiple reactive functional groups. However, this approach has been limited to the monomers involving simple alkene/alkyne moieties or produced mainly non‐degradable polymers. In this study, we demonstrate a complete cascade ring‐opening/ring‐closing metathesis polymerization (RORCMP) using various tricycloalkenes and two strategies for the efficient degradation. Through rational design of tricycloalkene monomers, the structure and reactivity relationship was explored. For example, tricycloalkenes with trans configuration in the central ring enabled faster and better selective cascade RORCMP than the corresponding cis isomers. Also, a 4‐substituted cyclopentene moiety in the monomers significantly enhanced the overall cascade RORCMP performance, with the maximum turnover number (TON) reaching almost 10,000 and molecular weight up to 170 kg/mol using an amide‐containing monomer. Furthermore, we achieved one‐shot cascade multiple olefin metathesis polymerization using tricycloalkenes and a diacrylate, to produce new highly A,B‐alternating copolymers with full degradability. Lastly, we successfully designed xylose‐based tricycloalkenes to give well‐defined polymers that underwent ultra‐fast and complete degradation under mild conditions. [ABSTRACT FROM AUTHOR]

We have accomplished the first and asymmetric total synthesis of principinol B, a grayanoid possessing an oxabicyclo[3.2.1] architecture. A functionalized 5/7/6/5 tetracyclic intermediate was assembled in a convergent manner by a diastereoselective intermolecular aldol reaction and subsequent carbonyl–olefin metathesis of two enantiomerically enriched fragments. The oxabicyclo[3.2.1] architecture containing a 6,10‐ether bridge was constructed by the Williamson ether synthesis. [ABSTRACT FROM AUTHOR]

By treating KSiiPr3 with Sn[N(SiMe3)2]2 the distannene Sn2(TIPS)4 (TIPS=SiiPr3) is formed in a metathesis reaction. The crystal structure analysis of Sn2(TIPS)4 reveals a planar arrangement of the substituents in the solid‐state and hence the second planar alkene like distannene of its kind. Due to the TIPS substituents, Sn2(TIPS)4 is well soluble in all commonly used organic solvents, opening the door for various analytics and reactivity studies. Due to its stability in solution, various reactions can be performed such as cycloaddition reactions with 2,3‐dimethyl‐1,3‐butadiene (DMBD) and TMS‐azide. [ABSTRACT FROM AUTHOR]

Neutral three‐coordinate iron alkylidenes of the form PN−Fe=CHR have been proposed as viable candidates for alkene metathesis. Indeed, during the final stages of preparing this current study, a separate report disclosed that dearomatized PN−Fe‐alkyl complexes are active precatalysts for ring‐opening metathesis polymerization (ROMP) of norbornene implicating PN−Fe=CHR species as possible intermediates. In yet another separate report, we prepared Zn analogues of PN−Fe‐alkyl complexes and herein provide an account for the synthesis, characterization, and reactivity of some new iron complexes with the same tBu substituted PN platform. [ABSTRACT FROM AUTHOR]

Synthesis of primary lanthanide amides in the bis‐hydrotris(1‐pyrazolyl)borate ligand environment has been achieved. Salt metathesis of [Dy(Tp)2(OTf)] 1‐Dy (OTf=CF3SO3) with K(N′′) (N′′=N(SiMe3)2) in toluene yielded the [bis(silyl)]amide [Dy(Tp)2(N′′)] 2‐Dy. Complexes 1‐Ln and 2‐Ln were both used to access primary lanthanide amides, where either metathesis of 1‐Ln with K(NHArCF3) (ArCF3=C6H3(CF3)2‐3,5) or protonolysis of 2‐Ln with H2NArCF3 in toluene yielded [Ln(Tp)2(NHArCF3)] 3‐Ln (Ln=Y, Dy). The synthesis of parent amides was also attempted, but the metathesis of 1‐Y with NaNH2 yielded complicated reaction mixtures, but from which the dimeric parent amide [{Y(Tp)2(μ‐NH2)}2] 4‐Y and an 'ate'‐salt [{Y(Tp)2(μ2‐OTf)(μ3‐OTf)Na(THF)2}2] 5‐Y were isolated. Full characterisation data are presented for all complexes, including the structure determination. [ABSTRACT FROM AUTHOR]

This article, published in the journal Synlett, examines the regioselectivity of metal-catalyzed aryne reactions. Arynes are reactive compounds used to synthesize valuable species, but these reactions often result in mixtures of regioisomeric products. The article discusses the regioselectivity of free arynes and the use of electronically influencing groups to induce regioselectivity. It also explores the lack of a regioselectivity model for metal-bound arynes and the potential for ligands to control regioselectivity in aryne transformations. The authors conducted experiments using different ligands and aryne precursors to determine their impact on regioselectivity, finding that factors such as ligand size, electron donation, and steric encumbrance of the aryne influence regioselectivity. The study demonstrates the potential of ligand control in inducing regioselectivity and provides insights into the factors governing metallated aryne selectivity. [Extracted from the article]

Enantiomerically enriched crown ethers (CE) exhibit strong asymmetric induction in phase transfer catalysis, supramolecular catalysis and molecular recognition processes. Traditional methods have often been used to access these valuable compounds, which limit their diversity and consequently their applicability. Herein, a practical catalytic method is described for the gram scale synthesis of a class of chiral CEs (aza‐crown ethers; ACEs) using Rh‐catalyzed hydroamination of bis(allenes) with diamines. Using this approach, a wide range of chiral vinyl functionalized CEs with ring sizes ranging from 12 to 36 have been successfully prepared in high yields of up to 92 %, dr of up to >20 : 1 and er of up to >99 : 1. These vinyl substituted CEs allow for further diversification giving facile access to various CE derivatives as well as to their three‐dimensional analogues using ring‐closing metathesis. Some of these chiral CEs themselves display high potential for use in asymmetric catalysis. [ABSTRACT FROM AUTHOR]

Cesium dicyanamide Cs[C2N3] (≡ Cs[N(CN)2] or Cs[dca]) was obtained by a metathesis reaction in form of transparent colorless platelets. The results of single-crystal X-ray structure measurements and refinements (C2/c, Z = 8) with the monoclinic cell parameters a = 932.31(8), b = 1274.67(9), c = 824.94(7) pm, β = 110.803(3)° at −70 °C and a = 939.59(7), b = 1281.58(8), c = 827.57(6) pm, β = 110.610(3)° at 20 °C corroborate earlier results for this compound. The Raman and IR spectra of Cs[C2N3] are presented for the first time and the result compares well with those of NaCs2[C2N3]3. The heat-driven cyclotrimerization process of Cs[C2N3] was studied by thermal analyses (DSC) and temperature-dependent X-ray powder diffraction methods. At 370 °C, its trimerization product Cs3[C6N9] is formed, crystallizing in the orthorhombic space group Pbam with the cell parameters a = 3043.0(3), b = 1052.4(1) and c = 415.21(4) pm for Z = 4. The IR spectrum of this cesium tricyanomelaminate (Cs3[C6N9] or Cs3[TCM]) is presented, but a well-resolved Raman spectrum could not be acquired owing to fluorescence phenomena. An overview about the cyclotrimerization reactions of all pseudo-binary alkali-metal dicyanamides (A[C2N3]) to their corresponding tricyanomelaminates (A3[C6N9]) with A = Li–Cs gives a basis for a discussion of the different thermal and structural characteristics. [ABSTRACT FROM AUTHOR]

The preparation of basalt and S‐glass fiber‐reinforced poly(dicyclopentadiene) via ring‐opening metathesis polymerization using a thermally latent pre‐catalyst, that is, Mo(N‐3,5‐Me2‐C6H3)(= CH‐(2‐MeO‐C6H4))(IMes)(OTf)2 (1, IMes = 1,3‐dimesitylimidazol‐2‐ylidene; OTf = SO3CF3) is reported. Complementarily, the non‐latent first‐generation Grubbs initiator RuCl2(PPh3)2(CHPh) (2) is used. 2 can be rendered latent by the addition of ppm amounts of triphenylphosphine (PPh3). Both 1 and 2/PPh3 allow the realization of thermally latent single‐component systems with sufficient pot life that do not require pre‐mixing of the individual components shortly before use. The prepared fiber matrix composites are characterized in terms of mechanical, thermal, and chemical stability. [ABSTRACT FROM AUTHOR]

[Carbonatotetraamminecobalt(III)] permanganate monohydrate was synthesized first in the metathesis reaction of [Co(NH3)4CO3]NO3 and NaMnO4 in aqueous solution. Its thermal dehydration at 100 °C resulted in phase-pure [Co(NH3)4CO3]MnO4 (compound 1). Compounds 1 and 2 (i.e., the hydrated form) were studied with IR, far-IR, and low-temperature Raman spectroscopies, and their vibrational modes were assigned. The lattice parameters were determined by powder X-ray diffraction (PXRD) and single crystal X-ray diffraction (SXRD) methods for the triclinic and orthorhombic compounds 1 and 2, respectively. The detailed structure of compound 2 was determined, and the role of hydrogen bonds in the structural motifs was clarified. UV studies on compounds 1 and 2 showed the distortion of the octahedral geometry of the complex cation during dehydration because of the partial loss of the hydrogen bonds between the crystal water and the ligands of the complex cation. The thermal decomposition consists of a solid phase quasi-intramolecular redox reaction between the ammonia ligands and permanganate anions with the formation of ammonia oxidation products (H2O, NO, N2O, and CO2). The solid phase reaction product is amorphous cobalt manganese oxide containing ammonium, carbonate (and nitrate) anions. The temperature-controlled thermal decomposition of compound 2 in toluene at 110 °C showed that one of the decomposition intermediates is ammonium nitrate. The decomposition intermediates are transformed into Co1.5Mn1.5O4 spinel with MnCo2O4 structure upon further heating. Solid compound 2 gave the spinel at 500 °C both in an inert and air atmosphere, whereas the sample pre-treated in toluene at 110 °C without and with the removal of ammonium nitrate by aqueous washing, gave the spinel already at 300 and 400 °C, respectively. The molten NH4NO3 is a medium to start spinel crystallization, but its decomposition stops further crystal growth of the spinel phase. By this procedure, the particle size of the spinel product as low as ~4.0 nm could be achieved for the treatments at 300 and 400 °C, and it increased only to 5.7 nm at 500 °C. The nano-sized mixed cobalt manganese oxides are potential candidates as Fischer-Tropsch catalysts. [ABSTRACT FROM AUTHOR]

A 1,1-bis(silylene)silole has been synthesised by a double salt-metathesis reaction from potassium silacyclopentadienediide, K2[1], and an amidinato-stabilized silylene chloride in a 1 : 2 ratio. The red colour of the title compound is due to the lp(Si)/π*(silole) transition. This band is bathochromically shifted compared to that of other 1,1-bissilylsiloles suggesting enhanced conjugation between the silole π-system and the newly formed Si(II)–Si(IV)–Si(II) group. The bissilylene is easily oxidised by the elemental chalcogens S, Se, and Te and forms a bissilaimide by reaction with an arylazide. [ABSTRACT FROM AUTHOR]

The Zweifel olefination is a highly efficient and versatile method for constructing carbon-carbon double bonds in organic synthesis. It avoids the use of transition metals and has been applied in natural product synthesis and drug discovery. Recent progress in the field includes the use of new organometallic species, electrochemical and photocatalyzed reactions, and exploration of milder reaction conditions. However, further research is needed to develop less functional-group-sensitive reagents and investigate new strategies for generating alkenyl boron complexes. [Extracted from the article]

The synthesis of ruthenium-complexes with cyclic (amino)(barrelene)carbenes (namely CABCs) as ligands is reported. Isolated in moderate to good yields, these new complexes showed impressive thermal stability at 110 °C over several days. Good catalytic performances were demonstrated in various ring-closing metathesis (RCM), macrocyclic–RCM, ring-closing enyne metathesis (RCEYM), cross-metathesis (CM), and ring-opening cross metathesis (ROCM) reactions. [ABSTRACT FROM AUTHOR]

We report the room temperature dimerization of carbon monoxide mediated by C4/C5‐vicinal anionic dicarbenes Li(ADC) (ADC = ArC{(Dipp)NC}2; Dipp = 2,6‐iPr2C6H3; Ar = Ph, DMP (4‐Me2NC6H4), Bp (4‐PhC6H4)) to yield (E)‐ethene‐1,2‐bis(olate) (i.e. −O−C=C−O− = COen) bridged mesoionic carbene (iMIC) lithium compounds COen‐[(iMIC)Li]2 (COen‐[iMIC]2 = [ArC{(Dipp)NC}2(CO)]2) in quantitative yields. COen‐[(iMIC)Li]2 are highly colored stable solids, exhibit a strikingly small HOMO–LUMO energy gap, and readily undergo 2e‐oxidations with selenium, CuCl (or CuCl2), and AgCl to afford the dinuclear compounds COon‐[(iMIC)E]2 (E = Se, CuCl, AgCl) featuring a 1,2‐dione bridged neutral bis‐iMIC (i.e. COon‐[iMIC]2 = [ArC{(Dipp)NC}2(C=O)]2). COen‐[(iMIC)Li]2 undergo redox‐neutral salt metathesis reactions with LiAlH4 and (Et2O)2BeBr2 and afford COen‐[(iMIC)AlH2]2 and COen‐[(iMIC)BeBr]2, in which the dianionic COen‐moiety remains intact. All compounds have been characterized by NMR spectroscopy, mass spectrometry, and X‐ray diffraction. Stereoelectronic properties of COon‐[iMIC]2 are quantified by experimental and theoretical methods. [ABSTRACT FROM AUTHOR]

A convenient method for Z → E geometry isomerization of aryl–aryl (stilbenes), alkyl–aryl, and alkyl–alkyl alkenes was developed. This user-friendly method utilized a popular commercial Hoveyda–Grubbs ruthenium olefin metathesis catalyst in the presence of sodium formate in toluene and is characterized by good functional group compatibility, including halogen, ester, aldehyde, and acetal functions. This research originated from trials on the valorization of a waste by-product resulting from the industrial synthesis of a valuable API—rosuvastatin. [ABSTRACT FROM AUTHOR]

The bis(yldiide) mercury complex, (L–Hg–L) [L = C(PPh3)P(S)Ph2], is prepared from the corresponding potassium yldiide and used to access the first substituted yldiide actinide complexes [(C5Me5)2An(L)(Cl)] (An = U, Th) via salt metathesis. Compared to previously reported phosphinocarbene complexes, the complexes exhibit long actinide–carbon distances, which can be explained by the strong polarization of the π-electron density toward carbon. [ABSTRACT FROM AUTHOR]

Efficient plastic recycling processes are crucial for the production of value‐added products or intermediates. Here, we present a multicatalytic route that allows the degradation of nitrile‐butadiene rubber, cross‐metathesis of the formed oligomers, and polymerization of the resulting dicarboxylic acids with bio‐based diols, providing direct access to unsaturated polyesters. This one‐pot approach combines the use of commercially available catalysts that are active and selective under mild conditions to synthesize renewable copolymers without the need to isolate intermediates. [ABSTRACT FROM AUTHOR]

Efficient plastic recycling processes are crucial for the production of value‐added products or intermediates. Here, we present a multicatalytic route that allows the degradation of nitrile‐butadiene rubber, cross‐metathesis of the formed oligomers, and polymerization of the resulting dicarboxylic acids with bio‐based diols, providing direct access to unsaturated polyesters. This one‐pot approach combines the use of commercially available catalysts that are active and selective under mild conditions to synthesize renewable copolymers without the need to isolate intermediates. [ABSTRACT FROM AUTHOR]

Branched bottlebrushes are a unique class of nanostructured polymers, and their versatile synthesis is of crucial significance. In this work, a bifunctional initiator was synthesized utilizing norbornene as the point of origin, incorporating bromide and Pd(II) complex in tandem. Branched bottlebrush copolymers comprising a mainchain of polynorbornene and branched side chains of a vinyl polymer and poly(phenyl isocyanide) were designed and prepared via the combination of atom transfer radical polymerization (ATRP), Pd(II)-initiated isocyanide polymerization, and ring opening metathesis polymerization (ROMP). Furthermore, a comprehensive characterization of the branched bottlebrushes has been conducted. [ABSTRACT FROM AUTHOR]

A simple dihydroxy isoquinolinium molecule (3+) was prepared by a modification of a literature procedure. Interestingly, during optimisation of the synthesis a small amount of the natural product pseudopalmatine was isolated, and characterised for the first time by X‐ray crystallography. Compound 3+ contains a catechol motif and positive charge on the same scaffold and was found to be a potent anion receptor, binding sulfate strongly in 8 : 2 d6‐acetone:D2O and 7 : 3 d6‐acetone:D2O (Ka>104 and 2,100 M−1, respectively). Unsurprisingly, chloride binding was much weaker, even in the less polar solvent mixture 9 : 1 d6‐acetone:D2O. The sulfate binding is remarkably strong for such a simple molecule, however anion binding studies were complicated by the tendency of the molecule to react with BPh4− or BF4− species during anion metathesis reactions. This gave two unusual zwitterions containing tetrahedral boronate centres, which were both characterised by X‐ray crystallography. [ABSTRACT FROM AUTHOR]

A rare asymmetric bicyclic polymer containing different length of conjugated polyacetylene segments is synthesized by metathesis cyclopolymerization‐mediated blocking‐cyclization technique. The size of each single ring differs from each other, and the unique cyclic polymer topology is controlled by adjusting the feed ratio of monofunctional monomer to catalyst. The topological difference between linear and bicyclic polymers is confirmed by several techniques, and the visualized morphology of asymmetric bicyclic polymer is directly observed without tedious post‐modification process. The photoelectric and thermal properties of polymers are investigated. This work expands the pathway for the derivation of cyclic polymers, and such unique topological structure enriches the diversity of cyclic polymer classes. [ABSTRACT FROM AUTHOR]

We have achieved the first total synthesis of bipolarolides A and B, which possess an intriguing and complex 5/6/6/6/5 caged pentacyclic skeleton with seven contiguous stereocenters. The synthesis features a lithium‐halogen exchange/intermolecular nucleophilic addition to link two enantioenriched fragments, two ring‐closing metathesis reactions to assemble the five‐ and eight‐membered rings, and a bioinspired Prins reaction/ether formation cascade cyclization to construct the 5/6/6/6/5 caged skeleton. [ABSTRACT FROM AUTHOR]

Guangnanmycin A is a recently discovered congener of the well‐known antitumor drug lead leinamycin; its macrolactam ring, however, is even more strained than that of the parent compound. The first synthetic foray towards this challenging target is reported, which relies on molybdenum‐catalyzed macrocyclization by ring closing alkyne metathesis (RCAM) followed by ruthenium‐catalyzed redox isomerization of the propargyl alcohol thus formed; the resulting enone enabled the introduction of the yet missing exo‐methylene group by a modified Peterson olefination. The signature disulfide moiety of guangnanmycin A was installed by strain‐driven thia‐Michael addition followed by conversion of the thioether thus formed into an unsymmetric disulfide with the aid of (methylthio)dimethylsulfonium tetrafluoroborate and MeSSMe. While this sequence furnished racemic guangnanmycin A alcohol in good overall yield, the final oxidation to the corresponding acid failed, most likely because of the exceptional sensitivity of the strained scaffold. [ABSTRACT FROM AUTHOR]

We have achieved the first total synthesis of bipolarolides A and B, which possess an intriguing and complex 5/6/6/6/5 caged pentacyclic skeleton with seven contiguous stereocenters. The synthesis features a lithium‐halogen exchange/intermolecular nucleophilic addition to link two enantioenriched fragments, two ring‐closing metathesis reactions to assemble the five‐ and eight‐membered rings, and a bioinspired Prins reaction/ether formation cascade cyclization to construct the 5/6/6/6/5 caged skeleton. [ABSTRACT FROM AUTHOR]

Guangnanmycin A is a recently discovered congener of the well‐known antitumor drug lead leinamycin; its macrolactam ring, however, is even more strained than that of the parent compound. The first synthetic foray towards this challenging target is reported, which relies on molybdenum‐catalyzed macrocyclization by ring closing alkyne metathesis (RCAM) followed by ruthenium‐catalyzed redox isomerization of the propargyl alcohol thus formed; the resulting enone enabled the introduction of the yet missing exo‐methylene group by a modified Peterson olefination. The signature disulfide moiety of guangnanmycin A was installed by strain‐driven thia‐Michael addition followed by conversion of the thioether thus formed into an unsymmetric disulfide with the aid of (methylthio)dimethylsulfonium tetrafluoroborate and MeSSMe. While this sequence furnished racemic guangnanmycin A alcohol in good overall yield, the final oxidation to the corresponding acid failed, most likely because of the exceptional sensitivity of the strained scaffold. [ABSTRACT FROM AUTHOR]

For sustainable application of chloroprene rubber (CR), a new technology is developed by the vulcanization of CR using 2,2'-dithiodipyridine (DPD) as a cross-linking agent with the reprocessing performance owing to disulfide metathesis. When DPD was incorporated into CR vulcanization, the Menschutkin reaction between allyl chloride group and pyridine group occurred with a maximum exothermic peak at 184°C. The number of effective cross-linking bond at 0.5 phr DPD vulcanizate was higher than that at high DPD content. This vulcanizate showed high tensile strength (11.12 MPa) and elongation at break (1253 ± 120%) owing to the exchangeable disulfide bond in the system. Under the catalysis of triphenylphosphine, the metathesis of disulfide compound was improved obviously, which endowed CR/DPD vulcanizates with good recyclability performance. Disulfide cross-linkage maintains its stability at low temperature, thus ensuring the mechanical stability of CR/DPD vulcanizate under the ambient conditions. Vulcanization and reprocessing of CR/DPD vulcanizate can be conducted with common industrial rubber processing equipment. Such reprocessable chloroprene rubber could have potential application in CR industry, also serve to significantly improve environmental sustainability. [ABSTRACT FROM AUTHOR]

The use of palm oil-derived polyol in polyurethane manufacturing is restricted owing to its poor hydroxyl value, which results in a suboptimal polyurethane network. Palm oil could be first chemically modified by cross metathesis (CM) into olefin and ester products with terminal double bonds prior to converting it to the polyols with optimum hydroxyl value. Due to the catalyst degradation and the unwanted self-metathesis reaction, the plant oil CM employing ethylene has been limited by its poor selectivity and low yield. The goal of present research is to investigate the palm oil CM using 1-octene from the aspects of parametric and kinetic analysis. The use of 1-octene was hypothesized to prevent the formation of undesired catalytic intermediates and hence allowing the ruthenium-based Hoveyda Grubbs second generation catalyst (2nd HGC) to maintain its activity and stability. Adopting one factorial at time (OFAT) in a batch system, the effect of different parameters on cross-metathesis of palm oil was examined. The variation in reaction time, temperature, reactant molar ratio of 1-octene to triolein (MOC/TR), and catalyst loadings were correlated to triolein conversion, yield, and selectivity of 1-decene. The products such as 1-decene and glyceryl tri-9-decenoate were quantified using Gas Chromatography-Mass Spectrometry (GC-MS). The maximum triolein conversion and 1-decene yield, 97.78% and 293.36% respectively, were obtained when the cross metathesis of palm oil using 1-octene occurred at 343 K for 2 h with MOC/TR of 8 and catalyst loading of 5 ppm. After three consecutive catalytic tests carried out at best operating condition, the insignificant decline in the reaction performance evidenced that the 2nd HGC catalyst remained active and stable. It was also found that the power-law model well predicted the concentration profile of the cross-metathesis of palm oil using 1-octene, estimating activation energy of 22583 J/mol. This study developed a new technically feasible process for adding value to palm oil, by enabling the use of palm oil as a feedstock for the production of polyol. [ABSTRACT FROM AUTHOR]