A metal‐free 2+2 cycloaddition and 1,4‐addition sequence induced by S‐centered radicals has been achieved by treating benzene‐linked allene‐ynes with aryldiazonium tetrafluoroborates and ...DABCO‐bis(sulfur dioxide) in a one‐pot procedure. The reaction provides a greener and more practical access to functionalized cyclobutaanaphthalen‐4‐ols with valuable applications. More than 50 examples are demonstrated with excellent diastereoselectivity and chemical yields. The reaction pathway is proposed to proceed by the following steps:2+2 cycloaddition, insertion of SO2, 1,4‐addition, diazotization, and tautomerization.
Just a DAB: A new metal‐free 2+2 cycloaddition/S‐centered radical induced 1,4‐addition sequence of benzene‐linked allene‐ynes has been established by treatment with aryldiazonium tetrafluoroborates and DABCO‐bis(sulfur dioxide) under convenient reaction conditions, thus providing practical access to functionalized cyclobutaanaphthalen‐4‐ols of chemical and biomedical importance. DABCO=1,4‐diazabicyclo2.2.2octane.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
To realize the molecular design of new functional silver(I) clusters, a new synthetic approach has been proposed, by which the weakly coordinating ligands NO3 – in a Ag20 thiolate cluster precursor ...can be substituted by carboxylic ligands while keeping its inner core intact. By rational design, novel atom-precise carboxylic or amino acid protected 20-core Ag(I)-thiolate clusters have been demonstrated for the first time. The fluorescence and electrochemical activity of the postmodified Ag20 clusters can be modulated by alrestatin or ferrocenecarboxylic acid substitution. More strikingly, when chiral amino acids were used as postmodified ligands, CD-activity was observed for the Ag20 clusters, unveiling an efficient way to obtain atom-precise chiral silver(I) clusters.
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New chiral targets of orientational chirality have been designed and asymmetrically synthesized by taking advantage of N‐sulfinyl imine‐directed nucleophilic addition/oxidation, Suzuki‐Miyaura, and ...Sonogashira cross‐coupling reactions. Orientation of single isomers has been selectively controlled by using aryl/alkynyl levers C(sp2)‐C(sp) axis and tBuSO2‐ protecting group on nitrogen as proven by X‐ray diffraction analysis. The key structural characteristic of resulting orientational products is shown by remote through‐space blocking manner. Seventeen examples of multi‐step synthesis were obtained with modest to good chemical yields and complete orientational selectivity.
We report herein the design of the asymmetric synthesis of orientational atropisomers via Sonogashira coupling as the key step. This new category of orientational atropisomers is anticipated to have a broad impact on chemical, biomedical, and material sciences in the future.
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Two 8,8′ disubstituted binaphthyl ligands have been designed and synthesized in 3.1% and 11.4% overall yield, respectively. X-ray structure analysis demonstrated that a unique chiral microenvironment ...was created. With the assistance of a new aggregation-induced polarization (AIP) technology, chiral aggregates were determined as the fraction of polar solvent increased in the nonpolar/polar solvent system, which indicated their potential in modern asymmetric synthesis and catalysis.
A new chiral phosphine ligand and its diol derivative have been designed and synthesized asymmetrically.
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Unprecedented chiral multilayer folding 3D polymers have been assembled and regulated by uniform and differentiated aromatic chromophore units between naphthyl piers. Screening catalysts, catalytic ...systems and monomers were proven to be crucial for asymmetric catalytic Suzuki–Miyaura polycouplings for this assembly. X‐ray crystallography of the corresponding dimers and trimers revealed the absolute configuration and the intermolecular packing pattern. Up to 61 960 Mw/41 900 Mn and m/z 4317 for polymers and oligomers, as confirmed by gel permeation chromatography (GPC) and MALDI‐TOF MS, indicated that these frameworks were composed of multiple stacked layers. The resulting multiple π‐assemblies exhibited remarkable optical properties in aggregated states (photoluminescence in solids and aggregation‐induced emission in solutions), as well as reversible redox properties in electrochemical performance.
A first asymmetric catalytic approach to multilayer 3D folding polymers by using Suzuki–Miyaura cross‐coupling in the presence of chiral catalysts. The resulting multiple π‐assemblies exhibited remarkable optical properties in aggregated states (photoluminescence in solids and aggregation‐induced emission in solutions), as well as reversible redox properties in electrochemical performance.
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Developing highly luminescent and extensively stable silver cluster‐assembled materials (SCAMs) from the inferior luminogens and unstable silver cluster is an important and challenging issue. Herein, ...a new luminescent three‐dimensional SCAM (Ag12CPPP, Ag12(StBu)6(CF3COO)6(CPPP)2(DMAc)12n; CPPP=2,5‐bis(4‐cyanophenyl)‐1,4‐bis(4‐(pyridine‐4‐yl)‐phenyl)‐1,4‐dihydropyrrolo3,2‐bpyrrole, DMAc=dimethylacetamide) was designed and synthesized with a quadridentate rigid emission ligand (CPPP) and a silver–chalcogenolate cluster (SCC) containing 12 AgI atoms. The luminescence study indicates that CPPP is an aggregation‐caused quenching (ACQ) molecule with twisted intramolecular charge transfer (TICT) character. Benefiting from the strong immobilization effect in the robust framework, the quantum yield of CPPP is greatly enhanced in Ag12CPPP compared with that of CPPP in solution or in the solid state. As a result, Ag12CPPP exhibits typical matrix coordination induced emission (MCIE) effect. Such efficient rigidifying methodology provides a promising approach for enhancing luminescence of ACQ molecules in an aggregated state and strengthening the silver cluster in an unstable state.
Cluster lighting: Matrix coordination induced emission (MCIE) effect was observed in a new three‐dimensional silver cluster‐assembled material (SCAM). The quantum yield (QY) of the SCAM is much higher than that of the quadridentate ligand (see figure).
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Silver chalcogenolate clusters (SCCs) and silver cluster‐assembled materials (SCAMs) are an important category of novel luminescent materials, the emission of which can be modulated by variation of ...the cluster nodes and linker species. Here, the successfully synthesis of two isostructural 2D SCAMs is reported: Ag12bpa and Ag12bpe are formed by using two linkers with different conformational freedom (bpa=1,2‐bis(4‐pyridyl)ethane, bpe=1,2‐bis(4‐pyridyl)ethylene), with dodenuclear silver chalcogenolate clusters as secondary building units (SBUs). Interestingly, nonluminescent Ag12bpa at room temperature could quickly transform into 1D Ag10bpa, with concomitant dissociation of two silver atoms and the remaining ten silver atoms rearranging in the cluster, thus exhibiting an intense yellow phosphorescence after being triggered by acetonitrile (CH3CN). Similarly, stimulating Ag12bpe with CH3CN, by contrast, gave another 2D structure Ag12bpe‐1b with the distorted SBUs and different topology structure, and both of them are merely red‐emissive at low temperature. To note, after exchanging ligands, room‐temperature nonluminescent 2D Ag12bpe‐1b can be transformed into intensely luminescent 1D Ag10bpa. This linker‐flexibility‐dependent structural transformation and cluster‐based SBU controlled luminescence remains scarce. Our work provides new insights into structure–luminescence relationship in clustered metal–organic frameworks and intelligent stimulus‐responsive luminescent materials.
What a SCAM! Isostructural silver cluster‐assembled materials (SCAMs) Ag12bpa and Ag12bpe (bpa=1,2‐bis(4‐pyridyl)ethane, bpe=1,2‐bis(4‐pyridyl)ethylene) were synthesized by using bidentate pyridine to give identical length yet different flexibility. Ag12bpa and Ag12bpe differently respond to acetonitrile: 2D Ag12bpa, which is only red‐emissive at low temperature transforms into yellow‐emissive 1D Ag10bpa at room temperature (see figure).
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Comprehensive Summary
Yne‐allenes bearing both a C—C triple bond and an allene unit are a class of focal substrates in organic synthesis, in view of their structure diversity, high reactivity and ...intermediate variety in the past years. Engaging yne‐allenes in numerous annulation cascades provides efficient and direct accesses to elaborate functionalized polycyclic molecular architectures in a convergent manner. There are lots of types of catalytic chemical reactions such as intramolecular cyclizations, cycloisomerizations, intermolecular annulations, and bicyclizations as well as tricyclizations with the assistance of Lewis acids, Brønsted acids, bases, transition metals, and other catalysts. This review provides an overview of the chemistry developed with transformations of yne‐allenes by discussing their general and specific reactivities, presenting and commenting on their mechanisms as well as their applications.
This review summarizes recent progress in the transformations of yne‐allenes with different structural features and focusing on reaction mechanisms. The aim of this article is to present a general overview of the possibilities offered to chemists using complementary catalytic modes and to emphasize advantages of the synthesis of cyclic structures on recently existing procedures and employed methodologies.
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The first thiazolium salt-catalyzed C-C triple bond cleavage of benzene-linked allene-ynes has been established. The reaction pathway involves 2+2 cycloaddition and ring-opening of in situ generated ...cyclobutenes with H
O under mild and convenient conditions, and provides practical access to substituted 1-naphthols with potentially valuable applications.
In this study, the design and asymmetric synthesis of a series of chiral targets of orientational chirality were conducted by taking advantage of
-sulfinylimine-assisted nucleophilic addition and ...modified Sonogashira catalytic coupling systems. Orientational isomers were controlled completely using alkynyl/alkynyl levers C(sp)-C(sp) axis with absolute configuration assignment determined by X-ray structural analysis. The key structural element of the resulting orientational chirality is uniquely characterized by remote through-space blocking. Forty examples of multi-step synthesis were performed, with modest to good yields and excellent orientational selectivity. Several chiral orientational amino targets are attached with scaffolds of natural and medicinal products, showing potential pharmaceutical and medical applications in the future.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
![Merging [2+2] Cycloaddition...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1433-7851/small "Merging [2+2] Cycloaddition with Radical 1,4‐Addition: Metal‐Free Access to Functionalized Cyclobuta[a]naphthalen‐4‐ols")
