Synthesis of C₃-symmetric star-shaped molecules containing α-amino acids and dipeptides via Negishi coupling as a key step

• Sambasivarao Kotha and
• Saidulu Todeti

Beilstein J. Org. Chem. 2019, 15, 371–377, doi:10.3762/bjoc.15.33

• peptide dendrimers. Keywords: amino acids; cyclotrimerization; Negishi coupling; peptide; Introduction Optically active C3-symmetric molecules are valuable synthons to design dendrimers, chiral ligands, polymers, and supramolecules [1][2][3][4]. In this regard, 1,3,5-triarylbenzene derivatives are

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• of 1.5 nm (Figure 1). The synthesis, structure and properties of POSS have been extensively reviewed [1][2][3]. Proper selection of organic substituents R allows the modification of solubility of POSS in reaction media, its compatibility with polymers, biological systems, or surfaces. The

• proposed synthetic method based on the gradual development of the organic part can be used for the synthesis of new star polymers, dendrimers or hyperbranched molecules. Further examples of the use of cross metathesis of OVS with styrenes in order to form functionalizable dendrimer cores have been reported

• the application of ADMET in the synthesis of oligomers or polymers containing a POSS unit in the main chain. Marciniec disclosed ADMET copolymerization of DDSQ-2SiVi with dienes in the stereoselective synthesis of a new class of vinylene–arylene copolymers containing double-decker silsesquioxanes in

Olefin metathesis in multiblock copolymer synthesis

• Maria L. Gringolts,
• Yulia I. Denisova,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2019, 15, 218–235, doi:10.3762/bjoc.15.21

• nanomaterials that combine various functional properties with durability and enhanced mechanical characteristics. Our mini-review addresses synthetic approaches to the design of multiblock copolymers from unsaturated monomers and polymers using olefin metathesis reactions and other ways of chemical modification

• across double C=C bonds. The main techniques, actively developed during the last decade and discussed here, are the coupling of end-functionalized blocks, sequential ring-opening metathesis polymerization, and cross metathesis between unsaturated polymers, or macromolecular cross metathesis. The last

• polymerization in a living fashion turned it into a powerful tool of polymer design [1]. Hundreds of linear, comb-like, graft-, bottle-brush, ladder, and other homopolymers and copolymers were synthesized [2][3][4][5][6][7]. Block copolymers combining properties of two or more individual polymers in one material

Catalysis of linear alkene metathesis by Grubbs-type ruthenium alkylidene complexes containing hemilabile α,α-diphenyl-(monosubstituted-pyridin-2-yl)methanolato ligands

• Tegene T. Tole,
• Johan H. L. Jordaan and
• Hermanus C. M. Vosloo

Beilstein J. Org. Chem. 2019, 15, 194–209, doi:10.3762/bjoc.15.19

• temperatures in the ROMP of norbornene and cyclooctene. Oligomers were obtained at room temperature in the presence of 4a and 4d, while 4b and 4c yielded polymers. At 60 °C, ROMP was observed with norbornene (98–100%) and cyclooctene (72–80%) in the presence of 4. We investigated a number of Grubbs 1- and

Fabrication of supramolecular cyclodextrin–fullerene nonwovens by electrospinning

• Hiroaki Yoshida,
• Ken Kikuta and
• Toshiyuki Kida

Beilstein J. Org. Chem. 2019, 15, 89–95, doi:10.3762/bjoc.15.10

• can be assembled into fibers/nonwovens by electrospinning. This result supports the notion that even small molecules (low-molecular weight compounds) with relatively weak inter/intramolecular interactions can be spun similar to the case of polymers. Since then, several small molecules, including

Selective ring-opening metathesis polymerization (ROMP) of cyclobutenes. Unsymmetrical ladderphane containing polycyclobutene and polynorbornene strands

• Yuan-Zhen Ke,
• Shou-Ling Huang,
• Guoqiao Lai and
• Tien-Yau Luh

Beilstein J. Org. Chem. 2019, 15, 44–51, doi:10.3762/bjoc.15.4

• corresponding soluble acetate. Both polymers are well characterized by spectroscopic means. No norbornene moiety is found to be incorporated into polycyclobutene strand at all. The double bonds in the polycyclobutene strand are mainly in cis configuration (ca 70%), whereas the E/Z ratio for polynorbornene

• strand is 8:1. Keywords: cyclobutene; hydrolysis; linker; metathesis; norbornene; ROMP; selectivity; unsymmetrical ladderphane; Introduction Ring-opening metathesis polymerizations (ROMP) of strained cycloalkenes offer a powerful arsenal for the synthesis of polymers having a variety of fascinating

• . Cyclopolymerization of 15 with a flexible linker. Methanolysis of unsymmetrical ladderphane 8. Supporting Information Supporting Information File 10: 1H and 13C NMR spectra of both monomers and polymers, as well as GPC and kinetic investigation results. Acknowledgement We thank the Ministry of Science and

Lectins of Mycobacterium tuberculosis – rarely studied proteins

• Katharina Kolbe,
• Sri Kumar Veleti,
• Norbert Reiling and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2019, 15, 1–15, doi:10.3762/bjoc.15.1

• )-branched α-D-arabinofuranoside-containing polymers [52]. LAM can further be peripherally modified, also known as ”capping“, the nature of which differs between mycobacterial species. In pathogenic mycobacteria, such as Mtb, LAM is capped to various degrees with one to three α-D-mannopyranosides [53], while

Ruthenium-based olefin metathesis catalysts with monodentate unsymmetrical NHC ligands

• Veronica Paradiso,
• Chiara Costabile and
• Fabia Grisi

Beilstein J. Org. Chem. 2018, 14, 3122–3149, doi:10.3762/bjoc.14.292

• ligand in 59 and 60 allowed for the selective formation of cyclic dimeric and trimeric products in place of polymers from cyclooctene, while the symmetrical analogues GII-SIMes and GII-IMes led mainly to polymers (Figure 15). Following a study on degenerate metathesis reactions that had highlighted a

• ). Importantly, later on Grubbs and co-workers utilized this kind of catalysts, featuring a chelating N-to-Ru arm, for the preparation of cyclic polymers from cyclic monomers via a ring-expansion metathesis polymerization (REMP) process [38][39]. With the aim of developing catalysts suitable for covalent

Degenerative xanthate transfer to olefins under visible-light photocatalysis

• Atsushi Kaga,
• Xiangyang Wu,
• Joel Yi Jie Lim,
• Hirohito Hayashi,
• Yunpeng Lu,
• Edwin K. L. Yeow and
• Shunsuke Chiba

Beilstein J. Org. Chem. 2018, 14, 3047–3058, doi:10.3762/bjoc.14.283

• thiocarbonylthio compounds has also been developed for the synthesis of the sequence-controlled oligomers [41][42][43][44][45]. For example, the group of Boyer and Xu developed fac-Ir(ppy)3 (6)-catalyzed polymerization of xanthate 4 with various vinyl monomers such as vinyl acetate, providing polymers of type 5

Organometallic vs organic photoredox catalysts for photocuring reactions in the visible region

• Aude-Héloise Bonardi,
• Frédéric Dumur,
• Guillaume Noirbent,
• Jacques Lalevée and
• Didier Gigmes

Beilstein J. Org. Chem. 2018, 14, 3025–3046, doi:10.3762/bjoc.14.282

• progresses achieved in terms of synthetic procedures allow now the access to polymers of well-defined composition, molecular weight and architecture. Thanks to these recent progresses in polymer engineering, the scope of applications of polymers is far wider than that of any other class of material, ranging

• used to produce the polymers. At present, most of the photoinitiating systems in use in the industry required high light intensity, the emission of these lamps being mainly centered in the UV range. To create safer photoinitiating systems, photoinitiators exhibiting a strong absorption in the near UV

• metal-based and metal-free photoredox catalyst [101]. 4 Photoredox catalysts in controlled radical polymerization Photoredox catalysis can also be used in a controlled free radical polymerization. The controlled radical polymerization is a powerful tool for the synthesis of polymers with precise average

Reactions of 3-(p-substituted-phenyl)-5-chloromethyl-1,2,4-oxadiazoles with KCN leading to acetonitriles and alkanes via a non-reductive decyanation pathway

• Akın Sağırlı and
• Yaşar Dürüst

Beilstein J. Org. Chem. 2018, 14, 3011–3017, doi:10.3762/bjoc.14.280

• bioactivities, such as anticancer [1], antimicrobial [2], antifungal [3], anti-inflammatory [4], tyrosine kinase inhibition [5] and histamine H3 antagonism properties [6]. In addition, these five-membered heterocycles were widely used as components of organic light emitting diodes (OLEDs), polymers, liquid

Copolymerization of epoxides with cyclic anhydrides catalyzed by dinuclear cobalt complexes

• Yo Hiranoi and
• Koji Nakano

Beilstein J. Org. Chem. 2018, 14, 2779–2788, doi:10.3762/bjoc.14.255

• synthetic method for polyesters as the polymers’ architectures and properties can be easily controlled depending on the combination of two monomers. Thus, a variety of catalyst designs has been reported to prepare the desired copolymers efficiently. We herein report dinuclear cobalt–salen complexes with a

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• , the catalyst was filtered, washed with chloroform and ethanol, and finally dried at 100 °C for 24 h. The catalyst was reused for four runs with good results (the yields of products ranged from 40 to 92%) [65]. A series of sulfonated polymers covalently grafted on multiwall carbon nanotubes (MWCNTs

• that these reactions are considered as typical model reactions in biodiesel production. To highlight the effect of acid groups, authors investigated the imidazolyl and pyridinyl polymers grafted on MWCTs for the transesterification of triglyceride 103 and low desired product (ranging from 12.3 to 15.1

• derivatives. The synthetic route for MWCNT-SO3H and its catalytic application for the synthesis of N-substituted pyrrole derivatives. The sulfonic acid-functionalized polymers (P-SO3H) covalently

Synthesis of a tyrosinase inhibitor by consecutive ethenolysis and cross-metathesis of crude cashew nutshell liquid

• Jacqueline Pollini,
• Valentina Bragoni and
• Lukas J. Gooßen

Beilstein J. Org. Chem. 2018, 14, 2737–2744, doi:10.3762/bjoc.14.252

• ][10]. These include aromatic amines as polymers [11][12], cardanol-based phosphates as modifiers for epoxy resins [13], cardanol grafted natural rubber as rubber plasticizers [14], amine-based surfactants [15] and phenol/cardanol-formaldehyde based adhesives [16]. The chemical valorization of

Learning from B₁₂ enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis

• Keishiro Tahara,
• Ling Pan,
• Toshikazu Ono and
• Yoshio Hisaeda

Beilstein J. Org. Chem. 2018, 14, 2553–2567, doi:10.3762/bjoc.14.232

• B12 [30]. Indeed, in the crystal structure, 1 maintained the same corrin framework as natural B12 [31]. We combined the hydrophobic B12 derivatives with bilayer vesicles [32][33], a protein [34], organic polymers [35][36][37][38][39][40], and metal organic frameworks (MOFs) [41]. Furthermore, to

Efficient catalytic alkyne metathesis with a fluoroalkoxy-supported ditungsten(III) complex

• Henrike Ehrhorn,
• Janin Schlösser,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2018, 14, 2425–2434, doi:10.3762/bjoc.14.220

• molybdenum propylidyne precursors to form chelate complexes of type IV [31][32][33][34]. These catalysts were especially successful in the construction of supramolecular materials such as ethynylene-linked polymers [11][35], porous networks [36] and molecular cages [37][38][39][40][41][42][43]. Furthermore

Non-metal-templated approaches to bis(borane) derivatives of macrocyclic dibridgehead diphosphines via alkene metathesis

• Tobias Fiedler,
• Michał Barbasiewicz,
• Michael Stollenz and
• John A. Gladysz

Beilstein J. Org. Chem. 2018, 14, 2354–2365, doi:10.3762/bjoc.14.211

• ) consisted of unidentified and/or impure products, or oligomers and polymers. Products that could be characterized are as follows (in order of elution). H3B·P(n-C8H17)3 (4·BH3 [33]; 0.007 g, 0.018 mmol, 1%), colorless oil. Anal. calcd for C24H54BP (384.47): C, 74.98; H, 14.16; found: C, 74.93; H, 14.02; 1H

• ·2BH3 (0.056 g, 0.083 mmol, 5%, minor impurities evident by 13C{1H} NMR), and (in,in/out,out)-2·2BH3 (0.075 g, 0.111 mmol, 7%), along with several fractions consisting of unidentified and/or impure products, or oligomers and polymers. Spectroscopic data for in,out-2·2BH3, (in,in/out,out)-2·2BH3, and 6

Hydroarylations by cobalt-catalyzed C–H activation

• Rajagopal Santhoshkumar and
• Chien-Hong Cheng

Beilstein J. Org. Chem. 2018, 14, 2266–2288, doi:10.3762/bjoc.14.202

• methodologies have been developed to build new C–X (X = carbon or heteroatom) bonds [7][8][9][10] and they offer efficient routes to the synthesis of natural products, materials, agrochemicals, polymers, and pharmaceuticals [11][12][13][14][15]. Specifically, the first-row transition metal catalysts, which are

Synergistic electrodeposition of bilayer films and analysis by Raman spectroscopy

• Saadeldin E. T. Elmasly,
• Luca Guerrini,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Neil J. Findlay,
• Karen Faulds and
• Peter J. Skabara

Beilstein J. Org. Chem. 2018, 14, 2186–2189, doi:10.3762/bjoc.14.191

• , which would be expected if there was a significant amount of de-doped PEDOT present [11]. The absorption profile of the bilayer therefore clearly shows the selective de-doping of PEDTT. It is evident from Figure 1 that the two polymers show electroactivity in distinctly different potential windows. This

• doped and de-doped mono-layers of PEDOT and PEDTT for comparison. Figure 2 shows the Raman spectra of pure PEDOT and PEDTT polymers, both in the doped and neutral states (Figure 2a and b, Figure 2c and d, respectively). There are two main spectral regions of interest in the Raman spectra of these

• polymers. Below approximately 1150 cm−1, the Raman spectra are dominated by medium to weak bands which can be predominantly assigned to out-of-plane deformations [12], which are only weakly sensitive to changes in the electronic properties of the polymers [13]. In comparing PEDOT and PEDTT, contributions

A switchable [2]rotaxane with two active alkenyl groups

• Xiu-Li Zheng,
• Rong-Rong Tao,
• Rui-Rui Gu,
• Wen-Zhi Wang and
• Da-Hui Qu

Beilstein J. Org. Chem. 2018, 14, 2074–2081, doi:10.3762/bjoc.14.181

• polymers. Keywords: alkenyl bond; functional crown ether; stimuli-responsiveness; switchable rotaxane; Introduction Along with the development of supramolecular chemistry, much attention has been paid to the design and synthesis of novel and complicated mechanical interlocked molecules (MIMs) [1][2][3][4

• functional groups, such kind of MIMs has been used to construct stimuli-responsive materials, which diversified and improved the functions of traditional polymers. Up to now, the repertoire of available functional rotaxanes as building blocks for the fabrication of stimuli-responsive polymers remains limited

• alkenyl units are reacted to generate polymers. On the other side, a naked alkenyl bond is introduced in the para position of the aromatic stopper. In the presence of external acid–base stimuli, the macrocyclic ring could be driven back and forth along the linear thread. Deprotonation of the DBA site by

Water-soluble SNS cationic palladium(II) complexes and their Suzuki–Miyaura cross-coupling reactions in aqueous medium

• Alphonse Fiebor,
• Richard Tia,
• Banothile C. E. Makhubela and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1859–1870, doi:10.3762/bjoc.14.160

• coupling reaction is a powerful method for the synthesis of ubiquitous biaryls and has been extensively employed in the synthesis of natural products, pharmaceuticals, agrochemicals, and polymers. The reaction usually involves a palladium-catalysed coupling of aryl boronates with aryl halides in organic

Graphitic carbon nitride prepared from urea as a photocatalyst for visible-light carbon dioxide reduction with the aid of a mononuclear ruthenium(II) complex

• Kazuhiko Maeda,
• Daehyeon An,
• Ryo Kuriki,
• Daling Lu and
• Osamu Ishitani

Beilstein J. Org. Chem. 2018, 14, 1806–1812, doi:10.3762/bjoc.14.153

• phase. Keywords: artificial photosynthesis; heterogeneous photocatalysis; hybrid material; metal complexes; solar fuels; Introduction Carbon nitride is one of the oldest synthetic polymers [1], and has several allotropes. Among them, graphitic carbon nitride (g-C3N4) is the most stable form and is an

Synthesis and photophysical studies of a multivalent photoreactive Ru^II-calix[4]arene complex bearing RGD-containing cyclopentapeptides

• Sofia Kajouj,
• Lionel Marcelis,
• Alice Mattiuzzi,
• Adrien Grassin,
• Damien Dufour,
• Pierre Van Antwerpen,
• Didier Boturyn,
• Eric Defrancq,
• Mathieu Surin,
• Julien De Winter,
• Pascal Gerbaux,
• Ivan Jabin and
• Cécile Moucheron

Beilstein J. Org. Chem. 2018, 14, 1758–1768, doi:10.3762/bjoc.14.150

• , Belgium Laboratory for Chemistry of Novel Materials, Center for Innovation and Research in Materials and Polymers, University of Mons – UMONS, 20, Place du Parc, B-7000 Mons, Belgium Organic synthesis and Mass Spectrometry Laboratory, University of Mons - UMONS, Place du Parc 23, B-7000 Mons, Belgium

Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit

• Cristina Morar,
• Pedro Lameiras,
• Attila Bende,
• Gabriel Katona,
• Emese Gál and
• Mircea Darabantu

Beilstein J. Org. Chem. 2018, 14, 1704–1722, doi:10.3762/bjoc.14.145

• −1), polymers (1679, 1625, 1622 and, presumably, even 1600 cm−1). Succeeding the ionic trimerisations, all these bands were absent in the IR spectra of 8 and 9, with the remaining carboxylate νC=O stretching band being located most likely at approximately 1600 cm−1. In conclusion, the exact

β-Hydroxy sulfides and their syntheses

• Mokgethwa B. Marakalala,
• Edwin M. Mmutlane and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143

• of 75–96% (Scheme 18). The reaction showed a broad substrate scope in terms of epoxides and aromatic thiols. Most recently, Kumar et al. synthesized Eu3+- and Tb3+-based coordination polymers (CPs) which function as reusable heterogeneous catalysts for ring-opening reactions utilizing amines