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The one-carbon ring expansion of benzocyclobutenones is an efficient methodology for the assembly of cyclic ketones. However, hazardous reagents or noble metal catalysts are frequently required. Herein, we disclose a copper-catalyzed intermolecular formal [4 + 1] annulation of 1,5-diynes with benzocyclobutenones, allowing the practical and atom-economical construction of diverse pyrryl 1-indanones in generally good yields under mild reaction conditions. This reaction represents an important advancement in the ring expansion of benzocyclobutenones via vinyl cation pathway.

The given text provides a detailed account of the synthesis and characterization of several chemical compounds. The compounds synthesized include 1-(2,4-Dichlorophenyl)-3-(2,4-dimethoxyphenyl)-5-(trimethylsilyl)-1,4-pentadiyne, Hexacarbonyl[μ-[(1,2-η:1,2-η)-1-(2,4-dichlorophenyl)-1,4-pentadiyn-3-ol]]dicobalt, Hexacarbonyl[μ-[(1,2-η:1,2-η)-1-(2,4-dichlorophenyl)-3-(2,4-dimethoxyphenyl)-1,4-pentadiyne]], 1-(2,4-Dichlorophenyl)-3-(2,4-dimethoxyphenyl)-1,4-pentadiyne, (Z)-1-(2,4-Dichlorophenyl)-3-(2,4-dimethoxyphenyl)-1,4-pentadiene, and (E)-1-(2,4-Dichlorophenyl)-3-(2,4-dimethoxyphenyl)-1,4-pentadiene. The synthesis procedures and characterization data, including IR, NMR, and HRMS spectra, are provided for each compound. The supporting information for the article is also [Extracted from the article]

We report an efficient iron-catalyzed cycloaddition procedure leading to the construction of (hetero)aromatic rings by alkyne [2+2+2] cycloisomerization. This method relies on the use of an air-stable (N,N)Fe(II) precursor easily prepared from a commercially available ligand derived from 1,10-phenanthroline, reduced in situ into a catalytically active non-innocent (N,N *-)2Fe(II) species. This system displays a large scope application, operates under mild conditions and at low catalytic charges (25 cycloadducts formed, up to 1.5 mol% catalyst). Moreover, this method also enables access to 29 cycloadducts by crosscycloisomerization between 1,6- or 1,7-diynes and alkynes in near-equimolar conditions. 1,3,5-Triazines can also be prepared with this procedure starting from the corresponding cyanamides. Scale-up reactions and post-functionalization of several cycloadducts also show that this [2+2+2] cycloaddition can be used in multistep sequences. [ABSTRACT FROM AUTHOR]

Herein we report that cycloheptatrienyl‐substituted 1,5‐diynes with aromatic backbones undergo a gold‐catalysed 5‐endo‐dig cyclisation to give 11H‐indeno‐[2,1‐a]azulenes at room temperature. This methodology complements the established range of aromatic structures obtained from gold‐catalysed conversions of differently substituted 1,5‐diynes accessed via highly reactive cationic intermediates. We have demonstrated the scope of the reaction and have assessed the possibility of further functionalisation of the indenoazulene scaffold. Additionally, we have studied the optical and electrochemical properties as well as the frontier molecular orbitals of this structural motif by both spectroscopic and theoretical means. [ABSTRACT FROM AUTHOR]

An efficient, highly selective and divergent synthetic method to construct 2‐substituted indoles and aryl‐annulated carbazoles via the intermolecular generation of α‐imino gold carbenes from terminal alkynes or diynes in combination with sulfilimines is disclosed. Importantly, the tandem reaction is proposed to proceed through an intermolecular gold carbene generation/C−H annulation followed by the activation of a second alkyne leading to 6‐endo‐dig cyclization, which is significantly different from previous dual activation or 1,6‐carbene shift approaches for diyne systems. In the case of ortho‐alkynylaniline as starting material, an unexpected regioselective formation of the indole moiety via the intermolecular path, instead of intramolecular hydroamination was discovered. This reactivity paved the way for a one‐pot synthesis of the 11H‐indolo [3,2‐c] quinoline scaffold by exploiting the formed amino indole for a subsequent Pictet–Spengler reaction with aldehydes. The photophysical properties of the carbazoles indicated good violet‐blue emission with quantum yields up to 40 %. [ABSTRACT FROM AUTHOR]

By employing the sterically highly demanding steering ligand IPr* at a gold(I) center, it is possible to induce a 6‐endo‐dig cyclization pathway in 1,5‐diynes bearing terminal alkyne moieties. The resulting aurated naphthyl cations are utilized for the intermolecular formation of C−C bonds via C−H insertion of aromatic and aliphatic C−H bonds. The mechanisms of these transformations were studied by quantum chemical calculations. [ABSTRACT FROM AUTHOR]

A novel methodology for the one-pot synthesis of unsymmetrical 1,3-butadiynes directly by the reaction of calcium carbide with aryl iodides is reported. This reaction system uses a safe, inexpensive, and easily handled acetylene source, and is easy to manipulate. This protocol is not only highly productive and selective, but also tolerates a wide range of functional groups. [ABSTRACT FROM AUTHOR]

Small heteroaryl‐diyne (Het‐DY) tags with distinct vibrational frequencies, and physiologically relevant cLog P were designed for multiplexed bioorthogonal Raman imaging. Pd−Cu catalyzed coupling, combined with the use of Lei ligand, was shown to improve overall yields of the desired heterocoupled Het‐DY tags, minimizing the production of homocoupled side‐products. Spectral data were in agreement with the trends predicted by DFT calculations and systematic introduction of electron‐ rich/poor rings stretched the frequency limit of aryl‐capped diynes (2209–2243 cm−1). The improved Log P of these Het‐DY tags was evident from their diffuse distribution in cellular uptake studies and functionalizing tags with organelle markers allowed the acquisition of location‐specific biological images. LC–MS‐ and NMR‐based assays showed that some heteroaryl‐capped internal alkynes are potential nucleophile traps with structure‐dependent reactivity. These biocompatible Het‐DY tags, equipped with covalent reactivity, open up new avenues for Raman bioorthogonal imaging. [ABSTRACT FROM AUTHOR]

An efficient copper-catalyzed oxidative cyclization of diynes is described. A range of functionalized γ-lactams can be readily constructed by using this protocol. This copper-catalyzed oxidative process proceeds through an alkyne oxidation, carbene/alkyne metathesis, and donor–donor carbene oxidation sequence. The use of readily available substrates, high flexibility, a simple procedure, and mild reaction conditions render the procedure a viable alternative for the preparation of functionalized γ-lactams. [ABSTRACT FROM AUTHOR]

We report on the use of anthracene α-diketone as a source of carbon monoxide (CO) in carbonylation reactions. Photoirradiation by a 5 W blue LED of a diyne in the presence of anthracene α-diketone and a rhodium(I) catalyst resulted in a [2+2+1]-carbonylative cycloaddition of the diyne to CO released from the anthracene α-diketone to give a high yield (up to 99%) of the corresponding cyclopentadienone. This is the first demonstration of a CO-gas-free carbonylation reaction using anthracene α-diketone. Light irradiation was a major factor both in the generation of CO from anthracene α-diketone and in the catalytic activity. A halogen lamp, a fluorescent lamp, or sunlight also served as a light source for this reaction. With this system, there is no need for an additional reagent for generating CO. [ABSTRACT FROM AUTHOR]

A Ni/N-heterocyclic carbene catalyst couples diynes to the C(α)-C(β) double bond of tropone, a type of reaction that is unprecedented for metal-catalyzed cycloadditions with aromatic tropone. Many different diynes were efficiently coupled to afford [5-6-7] fused tricyclic products, while [5-7-6] fused tricyclic compounds were obtained as minor byproducts in a few cases. The reaction has broad substrate scope and tolerates a wide range of functional groups, and excellent regioselectivity is found with unsymmetrical diynes. Theoretical calculations show that the apparent enone cycloaddition occurs through a distinctive 8π insertion of tropone. The initial intramolecular oxidative cyclization of diyne produces the nickelacyclopentadiene intermediate. This intermediate undergoes an 8π insertion of tropone, and subsequent reductive elimination generates the [5-6-7] fused tricyclic product. This initial product undergoes two competing isomerizations, leading to the observed [5-6-7] and [5-7-6] fused tricyclic products.

The reactivity of 5‐(alkynyl)dibenzothiophenium salts 1 is explored in the presence of different nucleophiles, dienes, and under photochemical conditions. Reaction with lithium acetylides affords diynes in moderate yields; while depending on the substitution pattern, the reaction with sulfinates delivers either the alkyne transfer products, alkynyl sulfones, or β‐(sulfonium) vinyl sulfones through addition to the C−C triple bond. Similar behavior is observed when tosylamines are used as nucleophiles. Salts of general formula 1 also react with dienes to render the corresponding Diels‐Alder cycloadducts. The vinyl sulfonium salts obtained by these routes further react with nucleophiles through a Michael addition, dibenzothiophene elimination sequence. Alternatively, they also engage in photoinduced radical cyclizations to produce substituted phenanthrenes. Attempts to use this specific addition/radical cyclization sequence for the construction of the 6a,7‐dehydroaporphine skeleton present in several families of alkaloids are also described. [ABSTRACT FROM AUTHOR]

Double branch (DB) dyes could reduce intermolecular interactions and realize good photovoltaic performances. Herein, symmetric DB dyes (FSDD‐1 and FSDD‐2) featuring with one and two acetylenic bonds as the isolation groups are reported. The corresponding single branch (SB) dye FSSD‐EH is synthesized for comparison. For the adsorption spectra, bathochromic shifts and higher ε are observed for DB dyes FSDD‐1 and FSDD‐2 compared with SB dye FSSD‐EH, which suggests better light‐harvesting capabilities for the DB dyes. Dye‐sensitized solar cells (DSSCs) sensitized by DB dyes FSDD‐1 and FSDD‐2 exhibit significant increases for the Jsc and Voc compared with SB dye FSSD‐EH, so much better η are achieved by the DB dyes (5.34, 7.14, and 2.46% for FSDD‐1, FSDD‐2, and FSSD‐EH, respectively). FSDD‐2 with a diyne unit exhibits higher η compared with FSDD‐1 with an yne unit as the isolation groups. The research shows that a much better photovoltaic performance of DSSCs can be achieved after connecting two dye molecules to be a DB dye by adopting acetylenic bonds as the isolation group. A longer distance between the two branches realized by a diyne unit is beneficial and effective to achieve better photovoltaic performance. [ABSTRACT FROM AUTHOR]

We describe Rh(I)‐catalyzed carbonylative [2+2+1] cycloaddition reactions of diynes with CO to give cyclopentadienone derivatives (CPDs). Previous reports on the use of neutral rhodium(I) complexes, such as [RhCl(cod)]2 and RhCl(PPh3)3, indicate that no CPD products are formed or that they are produced in low yields, even at elevated temperatures. The reaction described herein, which uses a cationic rhodium(I) complex, [Rh(cod)2]BF4, as a catalyst, proceeds smoothly at room temperature to give cyclopentadienone derivatives. The key to this is the use the cationic rhodium(I) complex as a catalyst, which produces an additional coordination site on the rhodium for the substrate (a diyne) to approach, than neutral rhodium complexes. [ABSTRACT FROM AUTHOR]

The jerangolids are a class of natural products with a skipped diene substructure isolated from Sorangium cellulosum. Here, we present a new strategy for the total synthesis of these compounds based on a skipped diyne as central building block and a suitably substituted epoxy aldehyde as building block for the dihydropyran substructure. So far, we reached an advanced intermediate which is related to the pharmacophore subunit of the jerangolids as well as of the ambruticins. A key step is a Shi epoxidation with high e.r. to form the epoxy aldehyde. Both building blocks are coupled in a Carreira alkynylation, where additional mechanistic studies based on DFT calculation were realized. The alkynylation is followed by a nucleophilic 6‐endo‐tet epoxide opening to form the pyran structure and a Nicholas reduction to remove a propargylic OH group. [ABSTRACT FROM AUTHOR]

The reaction of biradical [P(μ‐NTer)]2 (1, Ter = 2,6‐bis(2,4,6‐trimethylphenyl)phenyl) towards different alkenes (R = 2,3‐dimethyl–butadiene, 2,5‐dimethyl‐2,4‐hexadiene, 1,7‐octadiene, 1,4‐cyclohexadiene) and alkynes (R = 1,4‐diphenyl‐1,3‐butadiyne) was studied experimentally. Although these olefins can react in different ways, only [2+2] cycloaddition products (1R) were observed. The reaction with 2,3‐dimethylbutadiene also led to the [2+2] product (1dmb). Thermal treatment of 1dmb above 140 °C resulted in the recovery of biradical 1 upon homolytic bond cleavage of the two P–C bonds and the release of 2,3‐dimethylbutadiene. In contrast to this reaction, all other [2+2] additions products (1R, R = 1,7‐octadiene, 1,4‐cyclohexadiene, 1,4‐diphenyl‐1,3‐butadiyne) began to decompose at temperatures between 200 °C and 300 °C. Only unidentified products were obtained but no temperature‐controlled equilibrium reactions were observed. Computations were carried out to shed light into the formal [2+2] as well as the possible [4+2] addition reaction. [ABSTRACT FROM AUTHOR]

The reaction of biradical [P(μ‐NTer)]2 (1, Ter = 2,6‐bis(2,4,6‐trimethylphenyl)phenyl) towards different alkenes (R = 2,3‐dimethyl–butadiene, 2,5‐dimethyl‐2,4‐hexadiene, 1,7‐octadiene, 1,4‐cyclohexadiene) and alkynes (R = 1,4‐diphenyl‐1,3‐butadiyne) was studied experimentally. Although these olefins can react in different ways, only [2+2] cycloaddition products (1R) were observed. The reaction with 2,3‐dimethylbutadiene also led to the [2+2] product (1dmb). Thermal treatment of 1dmb above 140 °C resulted in the recovery of biradical 1 upon homolytic bond cleavage of the two P–C bonds and the release of 2,3‐dimethylbutadiene. In contrast to this reaction, all other [2+2] additions products (1R, R = 1,7‐octadiene, 1,4‐cyclohexadiene, 1,4‐diphenyl‐1,3‐butadiyne) began to decompose at temperatures between 200 °C and 300 °C. Only unidentified products were obtained but no temperature‐controlled equilibrium reactions were observed. Computations were carried out to shed light into the formal [2+2] as well as the possible [4+2] addition reaction. [ABSTRACT FROM AUTHOR]

Activation of NOD-like receptor protein 3 (NLRP3) inflammasome exacerbates liver inflammation and fibrosis in nonalcoholic steatohepatitis (NASH), suggesting that development of inflammasome inhibitor can become leading candidate to ameliorate NASH. Panax ginseng (P. ginseng) contains numerous bioactive natural components to reduce inflammation. This study aims to identify inhibitory components of P. ginseng for NLRP3 inflammasome activation. We separated polar and non-polar fractions of P. ginseng and tested modulation of NLRP3 inflammasome, and then identified pure component for inflammasome inhibitor which ameliorates diet-induced NASH. Non-polar P. ginseng fractions obtained from ethyl acetate solvent attenuated IL-1β secretion and expression of active caspase-1. We revealed that panaxydol (PND) is pure component to inhibit NLRP3 inflammasome activation. PND blocked inflammasome cytokines release, pyroptotic cell death, caspase-1 activation and specking of inflammasome complex. Inhibitory effect of PND was specific to NLRP3-dependent pathway via potential interaction with ATP binding motif of NLRP3. Moreover, in vivo studies showed that PND plays beneficial roles to reduce tissue inflammations through disruption of NLRP3 inflammasome and to ameliorate the development of NASH. These results provide new insight of natural products, panaxydol, for NLRP3 inflammasome inhibitor and could offer potential therapeutic candidate for reliving NASH., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

A ruthenium-catalyzed [2+2+2] cycloaddition between α,ω-diynes and cyanamides is reported under microwave irradiation to access 2-aminopyridines. In contrast to the classical thermal conditions, this atom-economical sustainable protocol allows access to diverse functionalized 2-aminopyridine derivatives with high yields and excellent regioselectivities in MeTHF with short reaction times. [ABSTRACT FROM AUTHOR]

Amide‐substituted diynes were cyclized in the presence of a cationic gold catalyst and an external nucleophile leading to 1‐indenones and 1‐iminoindenones. The electron‐donating features of the nitrogen atom enable the formation of a reactive ketene iminium ion, which can be trapped by either diphenyl sulfoxide or anthranil as nucleophiles in a subsequent oxidation step, providing substituted inden‐1‐on‐3‐carboxamides. [ABSTRACT FROM AUTHOR]

Series of various dienes, diynes and enynes were hydrosilylated in the presence of platinum complex [Pt(IPr*OMe)(dvms)] (I) (where IPr*OMe=1,3‐bis{2,6‐bis(diphenylmethyl)‐4‐methoxyphenyl}imidazol‐2‐ylidene, dvtms = divinyltetramethyldisiloxane) to afford selectively the corresponding mono‐ and bissilylated products in high yields. In each case, the process proceeded fully regioselectively according to the anti‐Markovnikov rule. Hydrosilylation of carbon–carbon triple bonds led to exclusive formation of E‐isomers. For the first time, a one‐pot sequential hydrosilylation of a selected 1,3‐enyne and symmetric α,ω‐diene with two different silanes was also achieved. Moreover, the optimized reaction conditions were adopted for successful hydrosilylation of 1,3‐enynes with secondary silanes to yield stereoregular polyenes containing terminal carbon–carbon double bonds. [ABSTRACT FROM AUTHOR]

A new mode of polymerization, rhodium‐catalyzed stitching polymerization, has been developed for the synthesis of π‐conjugated polymers with bridged repeating units from nonconjugated 1,5‐hexadiynes containing both terminal and internal alkyne moieties as monomers. The polymerization proceeded smoothly with a high degree of stitching efficiency under mild conditions, and 1,5,9‐decatriyne and 1,5,9,13‐tetradecatetrayne monomers could also be employed. The present polymerization strategy would be particularly beneficial for the synthesis of polymers consisting of a repeating unit that is difficult to prepare as a stable monomer because it does not require the use of a preformed bridged π‐conjugated monomer. A stitch in time saves... the preparation of a bridged π‐conjugated monomer: The title polymerization mode was developed for the synthesis of π‐conjugated polymers with bridged repeating units from nonconjugated oligoalkyne monomers containing both terminal and internal alkyne moieties (see scheme). The polymerization proceeded smoothly with a high degree of stitching efficiency under mild conditions. [ABSTRACT FROM AUTHOR]

It is well known that alkynes act as π‐acids in the formation of complexes with metals. We found unprecedented attractive Au–π interactions in diacetylene‐modified [core+exo]‐type [Au8]4+ clusters. The 4‐phenyl‐1,3‐butadiynyl‐modified cluster has unusually short Au–Cα distances in the crystal structure, revealing the presence of attractive interactions between the coordinating C≡C moieties and the neighboring bitetrahedral Au6 core, which is further supported by IR and NMR spectra. Such weak interactions are not found in mono‐acetylene‐modified clusters, which indicates that they are specific for diacetylenic ligands. The attractive Au–π interactions are likely associated with the low energy of the π* orbital in the diacetylenic moieties, into which the valence electrons of the gold core may be back donated. The [Au8]4+ clusters show clear red‐shifts of >10 nm with respect to the corresponding mono‐acetylenic clusters in UV/Vis absorption bands, which indicates substantial electronic perturbation effects of the Au–π interactions. A golden π‐crust: Unprecedented attractive Au–π interactions were found between a σ‐coordinating C≡C moiety and neighboring gold atoms of diacetylene‐modified Au8 clusters. The interaction was observed specifically for the diacetylenic ligands, and not found in the mono‐acetylenic analogues, indicating the uniqueness of the diacetylenic ligands. [ABSTRACT FROM AUTHOR]

Mn(I)-catalyzed selective functionalization of alkynes permits the convenient synthesis of substituted alkenes with high step and atom economies. Although the insertion of five-membered chelated manganacycle intermediates into alkynes has been widely reported, nonchelated Ar–Mn(I) species originating from commercially available arylboronic acids are unprecedented. Our new protocol achieved a challenging hydroarylation of unsymmetrical 1,3-diynes with arylboronic acids with complete regio-, stereo-, and chemoselectivity to give a wide array of trisubstituted conjugated (Z)-enynes in moderate to good yields. [ABSTRACT FROM AUTHOR]

β‐(2‐Alkynylphenyl)‐α,β‐ynones undergo a gold‐catalyzed oxidative two‐fold cyclization in the presence of N‐oxides to give 1,3‐disubstituted‐8H‐indeno[1,2‐c]furan‐8‐ones in good yields. This cascade process is triggered by a selective oxygen transfer from an N‐oxide onto the gold‐activated alkynone to generate a α‐dioxocarbene intermediate which, via carbene transfer across the remaining alkyne moiety and subsequent cyclization through nucleophilic attack by a carbonyl oxygen, achieves the construction of 1,3‐disubstituted fused polycyclic furans. [ABSTRACT FROM AUTHOR]

A library of ten 1,3-diyne-linked peptoids has been synthesized through an Ugi four-component reaction (U-4CR) followed by a copper-catalysed alkyne homocoupling (Glaser reaction). The short and chemoselective reaction sequence allows generating diverse (pseudo) dimeric peptoids. A combinatorial version allows the one-pot preparation of, e.g., six-compound-libraries of homo- and heterodimers verified by ESI-MS and HPLC. In a preliminary evaluation, some compounds display moderate activity against the Gram-positive bacterium Bacillus subtilis.

Abstract: The gold‐catalyzed annulation of diethynyl N‐heterocycles for the synthesis of quinoxaline‐/phenazine‐based pentalenes and the study of their optoelectronic properties are described. The inhibition of the gold catalyst by the nitrogen centers in the substrate and the product could be overcome by increasing the reaction temperature to 130 °C, which usually leads to catalyst decomposition in gold catalysis. At 130 °C, 6,7‐di(arylethynyl)quinoxalines in chlorobenzene give the corresponding pentalenes. The annulation of 2,3‐di(arylethynyl)quinoxalines requires an even higher temperature under microwave irradiation. The quinoxaline‐based pentalenes showed lower LUMO levels compared to the corresponding naphthalene‐based pentalenes. [ABSTRACT FROM AUTHOR]

Abstract: The benzylidyne complex [PhC≡W{OSi(OtBu)3}3] (1) catalyzed the cross‐metathesis between 1,4‐bis(trimethylsilyl)‐1,3‐butadiyne (2) and symmetrical 1,3‐diynes (3) efficiently, which gave access to TMS‐capped 1,3‐diynes RC≡C−C≡CSiMe3 (4). Diyne cross‐metathesis (DYCM) studies with 13C‐labeled diyne PhC≡13C−13C≡CPh (3*) revealed that this reaction proceeds through reversible carbon–carbon triple‐bond cleavage and formation according to the conventional mechanism of alkyne metathesis. The reaction between 1 and 3* afforded the 3‐phenylpropynylidyne complex PhC≡13C−13C≡W{OSi(OtBu)3}3] (5*), indicating that alkynylalkylidyne complexes are likely to act as catalytically active species. Attempts to isolate 5* from mixtures of 1 and 3* afforded crystals of the ditungsten 2‐butyne‐1,4‐diylidyne complex [(tBuO)3SiO}3W≡13C−13C≡13C−13C≡W{OSi(OtBu)3}3] (6*), which was additionally characterized by X‐ray diffraction analysis. Depolymerization‐macrocyclization of a carbazole‐butadiyne polymer, obtained from 3,6‐diethynyl‐9‐dodecylcarbazole (7) under copper‐catalyzed Hay coupling conditions, was also efficiently catalyzed by 1 and afforded a mixture of mono‐, diyne‐ and triyne‐containing tetrameric macrocycles, revealing that diyne disproportionation into monoynes and triynes occurs as a slow side reaction that interferes with a high diyne metathesis selectivity. Potential catalytic pathways were studied by means of quantum‐chemical calculations, and kinetic studies were performed to substantiate an α,α‐mechanism for the catalytic diyne metathesis reaction, which involves intermediate alkynylalkylidyne and α,α′‐dialkynylmetallacyclobutadiene intermediates. [ABSTRACT FROM AUTHOR]

An intermolecular efficient dimerization of diynes via Rh-catalyzed cycloaddition is presented. This protocol allows for the expedient synthesis of structurally diverse benzene derivatives, which retain an alkyne unit for post-functionalization to realize molecules with potential medicinal value and extended molecular complexity. The transformation is carried out in toluene and employs Rh(COD)2OTf3 as the metal source. Diversely decorated diynes tethered by nitrogen atom and ester were compatible with these conditions and furnished substituted benzenes with excellent selectivity. [ABSTRACT FROM AUTHOR]

The mechanisms of Cp∗Ru(cod)Cl-catalyzed cycloaddition of diynes with 2H-azirines has been theoretically investigated with the aid of density functional theory (DFT) calculations. Our calculated results indicate that the reductive elimination is the rate-determining step for this reaction. The steric effect is responsible for the observed selectivity. In addition, we studied the mechanisms when the substrate R1 is replaced by other substitutions. The corresponding calculated results are in reasonable agreement with the experimental observation. [ABSTRACT FROM AUTHOR]

By employing gold catalysis, starting from dialkynylated acenes a series of novel un-symmetrical aceno-annulated dibenzopentalenes has been prepared. The achieved yields range from 62–68 %. The fused systems contain naphthalene, anthracene, tetracene, and pentacene units. All new compounds are soluble and stable under standard conditions. The optical properties of the systems are dominated by the dibenzopentalene core for the smaller representatives, while for the anthracene-pentacene-based aceno-benzopentalenes the optical properties of the acene group dominates. Preliminary morphology tests on thin films showed a reverse trend between crystal size and molecule size. [ABSTRACT FROM AUTHOR]