Diels–Alder reaction of β-fluoro-β-nitrostyrenes with cyclic dienes

• Savva A. Ponomarev,
• Roman V. Larkovich,
• Alexander S. Aldoshin,
• Andrey A. Tabolin,
• Sema L. Ioffe,
• Jonathan Groß,
• Till Opatz and
• Valentine G. Nenajdenko

Beilstein J. Org. Chem. 2021, 17, 283–292, doi:10.3762/bjoc.17.27

• contains at least one fluorine atom [6][7][8]. Fluorinated functional materials have also found wide application as durable ion exchange membranes, e.g., in fuel cells [9][10][11], as thermoplastic polymers [12][13][14], in electronic and optoelectronic technologies [15], and in liquid crystal display

Insight into functionalized-macrocycles-guided supramolecular photocatalysis

• Minzan Zuo,
• Krishnasamy Velmurugan,
• Kaiya Wang,
• Xueqi Tian and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2021, 17, 139–155, doi:10.3762/bjoc.17.15

• on pillararene is a relatively new field, and only a few examples have been reported [53][54]. Wen and co-workers reported the selective photocatalytic oxidation of sulfides in the presence of conjugated macrocycle polymers (COP) with pillar[5]arene struts (Figure 17) [55]. The host–guest

• macrocycle-based polymeric nanocomposites can produce a better photocatalytic performance compared to the respective monomers and linear analogs due to their more accessible catalytic sites, whereas comparative studies are very limited. In addition, hyperbranched macrocycle-functionalized polymers can act as

Supramolecular polymers with reversed viscosity/temperature profile for application in motor oils

• Jan-Erik Ostwaldt,
• Christoph Hirschhäuser,
• Stefan K. Maier,
• Carsten Schmuck and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2021, 17, 105–114, doi:10.3762/bjoc.17.11

• , 64293 Darmstadt, Germany 10.3762/bjoc.17.11 Abstract We report novel supramolecular polymers, which possess a reversed viscosity/temperature profile. To this end, we developed a series of ditopic monomers featuring two self-complementary binding sites, either the guanidiniocarbonyl pyrrole carboxylic

• identification of one compound as a promising VII. Keywords: noncovalent interactions; polymers; ring-chain transformation; supramolecular chemistry; viscosity; Introduction Viscosity index improvers (VIIs) are used to counteract the loss of viscosity of working fluids (such as motor oils) at elevated

• highly cost effective due to their simple chemical nature. However, this also prevents their further development on a molecular level. For this reason, we set out to develop novel VIIs based on the formation of supramolecular polymers from low-molecular weight building blocks. This would allow for an in

Supramolecular polymerization of sulfated dendritic peptide amphiphiles into multivalent L-selectin binders

• David Straßburger,
• Svenja Herziger,
• Katharina Huth,
• Moritz Urschbach,
• Rainer Haag and
• Pol Besenius

Beilstein J. Org. Chem. 2021, 17, 97–104, doi:10.3762/bjoc.17.10

• of rigid supramolecular polymers. Since multivalent sulfated supramolecular structures mimic naturally occurring L-selectin ligands, the corresponding affinity was evaluated using a competitive SPR binding assay and benchmarked to an ethylene glycol-decorated supramolecular polymer. Keywords: L

• -selectin binders; multivalency; self-assembly in water; supramolecular polymers; Introduction Deciphering the interaction of artificial molecular building blocks with biological components is a key element on the way to understanding and selectively manipulating biological systems. Throughout nature

• polymers as a promising class of synthetic scaffolds [10][11][12][13][14]. Supramolecular polymers do provide additional features like a high degree of flexibility and excellent adaptivity, which are critical in biological interactions [15]. As water is the dominant solvent in biological systems, aqueous

Construction of pillar[4]arene[1]quinone–1,10-dibromodecane pseudorotaxanes in solution and in the solid state

• Xinru Sheng,
• Errui Li and
• Feihe Huang

Beilstein J. Org. Chem. 2020, 16, 2954–2959, doi:10.3762/bjoc.16.245

• , including molecular switches, molecular logic gates, molecular machines, supramolecular polymers, etc. [6][7][8][9][10][11]. Pseudorotaxanes not only are used as the supramolecular precursors for the synthesis of rotaxanes and catenanes but also play an important role in the construction of supramolecular

Using multiple self-sorting for switching functions in discrete multicomponent systems

• Amit Ghosh and
• Michael Schmittel

Beilstein J. Org. Chem. 2020, 16, 2831–2853, doi:10.3762/bjoc.16.233

• ‐stacking [15][16], dipole–dipole interactions [17] or hydrophobic interactions [18], have proven their significance as key players [19] in the creation of self-sorted supramolecular assemblies, such as 1D, 2D [20], and 3D architectures [21], polymers [22], gels [23], and most recently, of stand-alone

Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system

• David Liese,
• Hans Henning Wenk,
• Xin Lu,
• Jochen Kleinen and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2020, 16, 2820–2830, doi:10.3762/bjoc.16.232

• compared to polymers and also the sensorial properties (like stringiness) are more pleasant [18]. However, the quality of the lecithin needs to be very high so that reverse wormlike micelles can be formed [19] and the amount of the primer needs to be well balanced as was described by Shchipunov when

Selective recognition of ATP by multivalent nano-assemblies of bisimidazolium amphiphiles through “turn-on” fluorescence response

• Rakesh Biswas,
• Surya Ghosh,
• Shubhra Kanti Bhaumik and
• Supratim Banerjee

Beilstein J. Org. Chem. 2020, 16, 2728–2738, doi:10.3762/bjoc.16.223

• the receptor with their complementary binding partners in the target analyte [15]. One of the ways to design multivalent systems is to connect the receptors through covalent linkages. Conjugated polymers and conjugated polymer electrolytes are prominent examples of covalently constructed multivalent

• [36][37][38], conjugated polymers [39][40][41][42], quantum dots [43][44] and sensors based on organic receptors such as imidazolium, ammonium, guanidinium [45][46][47][48][49][50][51][52], etc. have also been developed. Imidazolium based synthetic receptors typically utilize a combination of

A heterobimetallic tetrahedron from a linear platinum(II)-bis(acetylide) metalloligand

• Matthias Hardy,
• Marianne Engeser and
• Arne Lützen

Beilstein J. Org. Chem. 2020, 16, 2701–2708, doi:10.3762/bjoc.16.220

• platinum(II)-bis(acetylide) complexes [46][47] proved useful as building blocks for the construction of polymers [48], rings [49][50] and cages [36][42][51]. These neutral compounds are usually easy-to-access, rather stable and the cis- and trans-isomers can be separated efficiently. In this work we

NMR Spectroscopy of supramolecular chemistry on protein surfaces

• Peter Bayer,
• Anja Matena and
• Christine Beuck

Beilstein J. Org. Chem. 2020, 16, 2505–2522, doi:10.3762/bjoc.16.203

• ], guanidiniocarbonylpyrrole (GCP) ligands [41][42][43][44][45][46], cucurbiturils [47][48][49][50][51], porphyrins [52][53][54][55][56][57][58][59][60], metal complexes [61][62][63], foldamers [64][65][66][67], nanoparticles [34][68], imprinted polymers [69][70][71][72], and dendrimers [73][74]. In this review, we focus

Dawn of a new era in industrial photochemistry: the scale-up of micro- and mesostructured photoreactors

• Emine Kayahan,
• Mathias Jacobs,
• Leen Braeken,
• Leen C.J. Thomassen,
• Simon Kuhn,
• Tom van Gerven and
• M. Enis Leblebici

Beilstein J. Org. Chem. 2020, 16, 2484–2504, doi:10.3762/bjoc.16.202

Computational tools for drawing, building and displaying carbohydrates: a visual guide

• Kanhaya Lal,
• Rafael Bermeo and
• Serge Perez

Beilstein J. Org. Chem. 2020, 16, 2448–2468, doi:10.3762/bjoc.16.199

• for preparing carbohydrate structures for atomistic simulations of glycoproteins, carbohydrate polymers and glycolipids using GROMACS [70][71] In the form of Python scripts; the tools are used to prepare the system, which generally includes the processing of a.pdb file using the pdb2gmx tool

• , it only uses the sugar units that are defined in GLYCAM. The topologies generated for glycosylated proteins and glycolipids are compatible with the OPLS [72] and AMBER [73] force fields. The topology for carbohydrate polymers is based on the GLYCAM force field. The user needs to provide the ceramide

Tools for generating and analyzing glycan microarray data

• Akul Y. Mehta,
• Jamie Heimburg-Molinaro and
• Richard D. Cummings

Beilstein J. Org. Chem. 2020, 16, 2260–2271, doi:10.3762/bjoc.16.187

• Akul Y. Mehta Jamie Heimburg-Molinaro Richard D. Cummings Department of Surgery, Beth Israel Deaconess Medical Center, National Center for Functional Glycomics, Harvard Medical School, Boston, MA, 02215, USA 10.3762/bjoc.16.187 Abstract Glycans are one of the major biological polymers found in

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• furnish compound 132 (Scheme 34). Since polyanilines are interesting π-conjugated polymers that contain characteristic conductivity by acid doping, environmental stability, optical and redox properties. Therefore, bridging of oligoaniline as a spacer between the functional units can lead toward the

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• of polymers for their applications as water-repellent, chemical-proof, lubricant and thermally- and electrically-insulating materials [24]. The importance of fluorine atoms in chemical crop protection agents is well-acknowledged because fluorine improves the biological activity and user safety

Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

• Edgar Peris,
• Raúl Porcar,
• María Macia,
• Jesús Alcázar,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159

• under continuous flow conditions. Results and Discussion Scheme 1 summarizes the synthetic approach used for the preparation of the functionalized polymers considered in this work. A commercially available PS-DVB bead-type macroporous chloromethylated polymer 1 (Merrifield resin with 20% DVB and 1.2

• mmol Cl/g,) was used as the starting material for the immobilization of N-arylimidazoles 2a and 2b, following the traditional alkylation protocol [18][19]. The preparation of these modified polymers was monitored by FT–ATR–IR, FT-Raman using a micro-spectroscopy accessory and the NBP test [20][21]. The

• confirmed that the SILLPs act as scavengers for the leached Pd species. Noteworthy, the larger palladium leaching did not lead to higher activities, suggesting that in absence of the SILLP some deactivation for the leached species was taking place. The TEM analysis of the polymers after the reactions showed

One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?

• Isaline Bonnin,
• Raphaël Mereau,
• Thierry Tassaing and
• Karine De Oliveira Vigier

Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143

• 10.3762/bjoc.16.143 Abstract The catalytic conversion of (ligno)cellulose is currently subject of intense research. Isosorbide is one of the interesting products that can be produced from (ligno)cellulose as it can be used for the synthesis of a wide range of pharmaceuticals, chemicals, and polymers

Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers

• Alberto Rubin Pedrazzo,
• Fabrizio Caldera,
• Marco Zanetti,
• Silvia Lucia Appleton,
• Nilesh Kumar Dhakar and
• Francesco Trotta

Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127

• crosslinked polymers made up of cyclodextrins. The reactive hydroxy groups of CDs allow them to act as multifunctional monomers capable of crosslinking to bi- or multifunctional chemicals. The most common NS synthetic pathway consists in dissolving the chosen CD and an appropriate crosslinker in organic polar

• . Polysaccharides and, among them, starch derivatives such as cyclodextrins (CD), have recently emerged as they are safe, of low cost and biodegradable. Cyclodextrin nanosponges (CD-NS) are crosslinked cyclodextrin polymers characterized by a nanosized three-dimensional network. The reactive hydroxy groups of CDs

• , applied to organic syntheses and polymers has gained growing interest in recent years [14][15][16][17][18]. Mechanochemical syntheses are safe and represent efficient activation methods for greener processes, avoiding the use of solvents and reducing energy consumption. Recently, many examples for

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• Shirakawa, leading to their shared award of the 2000 Chemistry Nobel Prize for “the discovery and development of conductive polymers” [101]. For the following 60 years, and still to this day, organic electronics is a vibrant field of research within materials chemistry and physics as a potential source of

• conjugation and polarisation of the surrounding medium, which is enhanced by low εr(ω) values [115][116][117][118]. The charge is transported in organic materials by “hopping” between the quantum states. The amorphous nature of most polymers produces a low symmetry and anisotropy for the charge transport

• . Hence, the charge mobility in organic semiconductors is typically much lower than in crystalline inorganic materials [115]. Conjugated polymers that are rigid will generally have faster intrachain charge transport rather than interlayer hopping transport (Figure 8) [107][115]. The process is highly

An overview on disulfide-catalyzed and -cocatalyzed photoreactions

• Yeersen Patehebieke

Beilstein J. Org. Chem. 2020, 16, 1418–1435, doi:10.3762/bjoc.16.118

• ; photocatalysis; thiyl radical; Introduction Organic disulfides are often used as the skeleton for drugs, pesticides, rubber auxiliaries, polymers, and electronic materials [1]. Over the past decade, organic disulfide-involving photoreactions have attracted increasing attention. Disulfides have versatile

• . In 1996, Burton and co-workers reported the stereoselective synthesis of cis-1,2-difluorotriethylsilyethylene and its conversion to a variety of cis-1,2-difluoroethylene synthons, which are important building blocks in the preparation of fluorine-containing pharmaceuticals, polymers, and bioactive

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

• of the richest families of stable and persistent organic radicals with applications ranging from catalysis of selective oxidation processes and mechanistic studies to production of polymers, energy storage, magnetic materials design and spectroscopic studies of biological objects. Compared to other N

• used in the development of organic magnetic materials [1], organic batteries [2][3][4], in the preparation of polymers by living polymerization [5][6], in the studies of biomolecules and living systems by EPR [7] and NMR [8] techniques. Stable N-oxyl radicals occupy a central place in organic chemistry

Synthesis and properties of tetrathiafulvalenes bearing 6-aryl-1,4-dithiafulvenes

• Aya Yoshimura,
• Hitoshi Kimura,
• Kohei Kagawa,
• Mayuka Yoshioka,
• Toshiki Itou,
• Dhananjayan Vasu,
• Takashi Shirahata,
• Hideki Yorimitsu and
• Yohji Misaki

Beilstein J. Org. Chem. 2020, 16, 974–981, doi:10.3762/bjoc.16.86

• ion complexes with DDQ or iodine were reported [17][18][19][20][21][22][23][24]. Peripherally thiophene-functionalized TTFs, as potential precursors to conducting polymers, and organic metals were also prepared and characterized [25][26][27][28][29]. To design more tempting molecules, the attachment

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• recovery and reuse. The authors did not observe any decrease in the photocatalytic activity of the material even after four reuses. Another very promising catalytic platform for this transformation is the covalent organic framework (COF), a class of porous crystalline polymers built from molecular building

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

• alternatives such as rylenes [56] or conjugated polymers [57] with the focus to receive materials covering a broad absorption range up to the near infrared (NIR) part. Nevertheless, they have not reached the necessary practical use as cyanines explainable by the modest solubility in many industrial matrix

• review provides available references disclosing controlled polymer synthesis via photoinduced electron transfer reactions [129]. In addition to those approaches, photo-induced ATRP has been widely used to synthesize well-defined polymers by controlled radical polymerization either with or without heavy

• , zwitterionic and anionic patterns shown in Scheme 10. The polymers obtained exhibited quite high molecular weights (more than 2 × 105 g·mol−1) and failed to exhibit living character [81]. However, this system exhibited a successful route with Cu(II) catalysts at the ppm scale [81]. Quite recently, NIR light

Room-temperature Pd/Ag direct arylation enabled by a radical pathway

• Amy L. Mayhugh and
• Christine K. Luscombe

Beilstein J. Org. Chem. 2020, 16, 384–390, doi:10.3762/bjoc.16.36

• radical; visible light; Introduction π-Conjugated polymers are of significant interest as they have the potential to combine the mechanical flexibility and affordability of synthetic polymers with the optical and electronic properties of semiconductors. One of the limitations to this field’s continued

• reduce waste and toxicity by removing the need for stoichiometric amounts of toxic organometallics [2]. While significant progress has been made in DArP, C–H bonds are more challenging to functionalize than their C–M counterparts. Known DArP conditions have limited monomers that can produce polymers with