An overview of the cycloaddition chemistry of fulvenes and emerging applications

• Ellen Swan,
• Kirsten Platts and
• Anton Blencowe

Beilstein J. Org. Chem. 2019, 15, 2113–2132, doi:10.3762/bjoc.15.209

• reported by Boul et al. Reactions occur between a pentafulvene and dicyanoethylenecarboxylate or tricyanoethylenecarboxylate [189]. Polymerisation and dynamer formation via Diels–Alder cycloaddition between fulvene groups in polyethylene glycol bis(fulvene) and bis(tricyanoethylenecarboxylate) derivatives

• [190]. Preparation of hydrogels via Diels–Alder cycloaddition with fulvene-conjugated dextran and dichloromaleic acid-modified poly(ethylene glycol) [191]. Ring-opening metathesis polymerisation of norbornene derivatives derived from fulvenes and maleimides to furnish facially amphiphilic polymers

Analysis of sesquiterpene hydrocarbons in grape berry exocarp (Vitis vinifera L.) using in vivo-labeling and comprehensive two-dimensional gas chromatography–mass spectrometry (GC×GC–MS)

• Philipp P. Könen and
• Matthias Wüst

Beilstein J. Org. Chem. 2019, 15, 1945–1961, doi:10.3762/bjoc.15.190

• consisted of a 30 m × 0.25 mm i.d. × 0.25 µm df DB-WAX Ultra Inert (Agilent Technologies, Bellefonte, PA, U.S.A.) as a high polar primary column with poly(ethylene glycol) as stationary phase coupled to a 1.7 m × 0.10 mm i.d. × 0.10 µm df MEGA-17 MS FAST (MEGA s.n.c., Legnano, MI, IT) moderately polar

Synthesis of a [6]rotaxane with singly threaded γ-cyclodextrins as a single stereoisomer

• Jason Yin Hei Man and
• Ho Yu Au-Yeung

Beilstein J. Org. Chem. 2019, 15, 1829–1837, doi:10.3762/bjoc.15.177

• have been synthesized via a threading-followed-by-stoppering approach. Due to the orthogonal binding of CB[6] to ammonium and γ-CD to biphenylene/tetra(ethylene glycol), the [n]rotaxanes display a specific sequence of the interlocked macrocycles. In addition, despite of the asymmetry of γ-CD with

• orthogonal binding of γ-CD to biphenylene and tetra(ethylene glycol) and CB[6] to ammonium, [n]rotaxanes of only a specific sequence of the interlocked macrocycles were obtained despite of the possibility of other sequence isomers. In addition, the three γ-CDs in the [6]rotaxane were found to adopt only one

• by LC–MS. Contrary to most reports on the inclusion of simple aromatic or poly(ethylene glycol) in γ-CD where a 2:1 binding stoichiometry was observed, LC–MS analysis of the reaction mixture containing a 2:1 molar ratio of 1/γ-CD stoppered by 2 showed only the [3]rotaxane 3R (93%, m/z = 798.0, 4

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells

• Quentin Huaulmé,
• Cyril Aumaitre,
• Outi Vilhelmiina Kontkanen,
• David Beljonne,
• Alexandra Sutter,
• Gilles Ulrich,
• Renaud Demadrille and
• Nicolas Leclerc

Beilstein J. Org. Chem. 2019, 15, 1758–1768, doi:10.3762/bjoc.15.169

• level may arise from the overall size of the molecule BOD-TTPA-alk that displays 4 alkyl chains and 2 ethylene glycol chains. The bigger size of BOD-TTPA-alk can eventually prevents its diffusion through all the pores of the TiO2 layer or decreases the density of grafted molecules due to steric

A novel three-component reaction between isocyanides, alcohols or thiols and elemental sulfur: a mild, catalyst-free approach towards O-thiocarbamates and dithiocarbamates

• András György Németh,
• György Miklós Keserű and
• Péter Ábrányi-Balogh

Beilstein J. Org. Chem. 2019, 15, 1523–1533, doi:10.3762/bjoc.15.155

• %, respectively) that might be attributed either to steric hindrance or the growing instability of the conjugate base of the secondary and tertiary alcohol, respectively. The present method provided the allylic derivative 3j in 72% yield, however, applying ethylene glycol resulted in 3k in 34% yield only. In the

A heteroditopic macrocycle as organocatalytic nanoreactor for pyrroloacridinone synthesis in water

• Piyali Sarkar,
• Sayan Sarkar and
• Pradyut Ghosh

Beilstein J. Org. Chem. 2019, 15, 1505–1514, doi:10.3762/bjoc.15.152

• the product was detected when the reaction was carried out in ethanol/water 1:1 (Table 1, entry 12). Even when repeating the reaction in the presence of the phase-transfer catalyst, poly(ethylene glycol) (PEG) no mentionable yield of product was observed (Table 1, entries 13 and 14). The subsequent

Reaction of oxiranes with cyclodextrins under high-energy ball-milling conditions

• László Jicsinszky,
• Federica Calsolaro,
• Katia Martina,
• Fabio Bucciol,
• Maela Manzoli and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2019, 15, 1448–1459, doi:10.3762/bjoc.15.145

• make the formation of (oligo)propylene glycol (oligo-PGs) unavoidable. Moreover, at higher degree of substitution (DS, number of substituent/macrocycle) the HP moiety can be further substituted, giving oligo-PG sidechains on the CDs [6]. At low DS values, occasional residual unsubstituted CDs can be

Reversible end-to-end assembly of selectively functionalized gold nanorods by light-responsive arylazopyrazole–cyclodextrin interaction

• Maximilian Niehues,
• Patricia Tegeder and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2019, 15, 1407–1415, doi:10.3762/bjoc.15.140

• of gold nanorods (AuNR) by thiolated cyclodextrin (CD) host molecules. As a result of the complete removal of the precursor capping agent cetyltrimethylammonium bromide (CTAB) by a tetraethylene glycol derivative, competitive binding to the host cavity was prevented, and reversible, light-responsive

• AuNR are functionalized selectively in a two-step ligand exchange reaction. The ends are capped with per-6-thio-β-cyclodextrin (tCD) and CTAB is removed from the remaining surface by monothiolated tetraethylene glycol (tTEG) enabling reversible host–guest chemistry. The addition of a divalent AAP

• thiols by a known two-step synthesis [42][43] to give a multivalent ligand (tCD) that is tightly bound to the gold surface and is not replaced by an excess of monothiolated tetraethylene glycol (tTEG). It is important to note the importance of the addition of ethanol during the ligand exchange to

Complexation of a guanidinium-modified calixarene with diverse dyes and investigation of the corresponding photophysical response

• Yu-Ying Wang,
• Yong Kong,
• Zhe Zheng,
• Wen-Chao Geng,
• Zi-Yi Zhao,
• Hongwei Sun and
• Dong-Sheng Guo

Beilstein J. Org. Chem. 2019, 15, 1394–1406, doi:10.3762/bjoc.15.139

• , respectively, by plotting the maximum emission wavenumbers of 2,6-TNS/1,8-ANS in a set of solvents as a function of solvent polarity ET(30) (Figure 1e and 1f). ET(30) values for the involved solvents (water, methanol, ethanol, propanol, butanol, glycerol and ethylene glycol) and the maximum emission

One-pot activation–alkynylation–cyclization synthesis of 1,5-diacyl-5-hydroxypyrazolines in a consecutive three-component fashion

• Christina Görgen,
• Katharina Boden,
• Guido J. Reiss,
• Walter Frank and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2019, 15, 1360–1370, doi:10.3762/bjoc.15.136

• to achieve full conversion with very good to excellent yields of isolated 1,5-diacyl-5-hydroxypyrazoline 5b (Table 1, entries 12–16). Although ethylene glycol as a cosolvent (Table 1, entry 13) gave slightly higher yields and ethanol furnished slightly lower yields (Table 1, entry 14), 2

Self-assembly behaviors of perylene- and naphthalene-crown macrocycle conjugates in aqueous medium

• Xin Shen,
• Bo Li,
• Tiezheng Pan,
• Jianfeng Wu,
• Yangxin Wang,
• Jie Shang,
• Yan Ge,
• Lin Jin and
• Zhenhui Qi

Beilstein J. Org. Chem. 2019, 15, 1203–1209, doi:10.3762/bjoc.15.117

• with their linear glycol chain counterparts, B21C7 shows great potential to be an easy-to-accessed building block to probe the non-covalent interactions and chemical transformations influenced by water molecules. Perylene diimide (PDI) and naphthalene diimide (NDI) are polycyclic aromatic chromophores

• conjugate B21C7 onto PDI, compound 3 and 4-dimethylaminopyridine (DMAP) were dissolved in ethylene glycol, then 3,4,9,10-perylenetetracarboxylic dianhydride (PDI) was charged and suspended in the solution. The mixture was heated to 140 °C and stirred overnight. After cooling down to room temperature, the

• trioligo(ethylene glycol)-conjugated PDI system which can self-assemble into similar nanobelt structures [79]. Therefore, we inferred that the B21C7 macrocycle units have a similar solubilizing and induction effect like oligo(ethylene glycol) chains for the self-assembly behavior of PDI derivatives. Due to

Design, synthesis and spectroscopic properties of crown ether-capped dibenzotetraaza[14]annulenes

• Krzysztof M. Zwoliński and
• Julita Eilmes

Beilstein J. Org. Chem. 2019, 15, 617–622, doi:10.3762/bjoc.15.57

• showed cation and solvent-induced dimerisation. More recently, Raston et al. reported the synthesis of Goedken’s macrocycle tmtaa nickel(II) complex featuring a single oligo(ethylene glycol) chain strapped across the face of the DBTAA macrocyclic core [28]. However, to the best of our knowledge, there

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• analogues (Scheme 8). However, catalysts 1 and 2 are unstable in water and their use is limited to ROMP. Polyethylene glycol (PEG)-tagged catalysts (10 and 11, Figure 1c) showed significantly improved RCM activities in water, but they tend to form aggregates in water due to their high molecular weight (ca

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives

• Mikhail V. Makarov and
• Marie E. Migaud

Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36

• performed by bubbling anhydrous ammonia gas into a suspension of anhydrous 5-phosphoribose in anhydrous ethylene glycol. After reaction completion, ammonia was removed under reduced pressure and the 5-phosphorylated aminoribose 28 reacted with N-(2,4-dinitrophenyl)-3-carbamoylpyridinium chloride (22) 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

• the nanoparticles were formed by a ABCBA pentablock copolymer. In this polymer A stands for hydrophilic oligo(ethylene glycol) (OEG)-grafted polynorbornene possessing stealth-like and antifouling properties that are useful for in vivo applications. The B block is formed by polynorbornene

• -substituted NB with poly(ethylene glycol) (PEG) [69]. Ring-opening metathesis copolymerization of the rather strained cyclooctene (COE) and a strainless 27-membered macrocyclic olefin (MCO) led to the multiblock copolymer consisting of octenylene blocks linked with ring-opened MCO segments (Scheme 6) [70

Silanediol versus chlorosilanol: hydrolyses and hydrogen-bonding catalyses with fenchole-based silanes

• Falco Fox,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2019, 15, 167–186, doi:10.3762/bjoc.15.17

• for side attack mechanism (Table 3, entry 10)) than the first. In accordance with the kinetic study, dichlorosilane 13 hydrolysed faster than BIFOXSiCl2 (7, Scheme 4). In addition, the hydrolysis of glycol-based dichlorosilane (Table 3, entries 11 and 12) and tetrachlorosilane (Table 3, entries 13 to

• 16) is computed as model system. The first hydrolytic step of SiCl4 has a higher energy barrier (Ea = 28.4 kcal mol−1, Table 3, entry 13) than 13 to 13ClOH (Ea = 27.7 kcal mol−1, Table 3, entry 7) and 13ClOH to 1 (Ea = 29.1 kcal mol−1, Table 3, entry 9). The glycol-substituted dichlorosilane has a

Ammonium-tagged ruthenium-based catalysts for olefin metathesis in aqueous media under ultrasound and microwave irradiation

• Łukasz Gułajski,
• Andrzej Tracz,
• Katarzyna Urbaniak,
• Stefan J. Czarnocki,
• Michał Bieniek and
• Tomasz K. Olszewski

Beilstein J. Org. Chem. 2019, 15, 160–166, doi:10.3762/bjoc.15.16

• ], dodecyltrimethylammonium bromide (DTAB) [36], polymerised cyclooctadiene (COD) and cyclooctene (COE) [37], sodium dodecyl sulphate (SDS) [38] or DL-α-tocopherol methoxypolyethylene glycol succinate solution (TPGS-750-M) [39], to improve the solubility of reacting species and/or performance of the catalyst. Recent progress

Copper(I)-catalyzed tandem reaction: synthesis of 1,4-disubstituted 1,2,3-triazoles from alkyl diacyl peroxides, azidotrimethylsilane, and alkynes

• Muhammad Israr,
• Changqing Ye,
• Munira Taj Muhammad,
• Yajun Li and
• Hongli Bao

Beilstein J. Org. Chem. 2018, 14, 2916–2922, doi:10.3762/bjoc.14.270

• Muhammad Israr Changqing Ye Munira Taj Muhammad Yajun Li Hongli Bao Key Laboratory of Coal to Ethylene Glycol and Its Related Technology, State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Center for Excellence in Molecular Synthesis, Chinese

Olefin metathesis catalysts embedded in β-barrel proteins: creating artificial metalloproteins for olefin metathesis

• Daniel F. Sauer,
• Johannes Schiffels,
• Takashi Hayashi,
• Ulrich Schwaneberg and
• Jun Okuda

Beilstein J. Org. Chem. 2018, 14, 2861–2871, doi:10.3762/bjoc.14.265

• catalyst and carbohydrate or small polyethylene glycol (PEG) groups were attached [11]. As another strategy to modify a protein surface with olefin metathesis, Isarov and Pokorski introduced a Grubbs 3rd generation catalyst on the surface of lysozyme and performed ring-opening metathesis polymerization

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

• [15]. The ee of propylene glycol, which was obtained after hydrolysis of the copolymer obtained with (S)-PO and PA, was found to be 88%, indicating a high level of regioregularity. Molecular weight distributions are relatively narrow, while a bimodal distribution was observed in the SEC traces. The

• ). The solvents were removed under reduced pressure and Et2O (5 mL) was added to the resulting powder. After stirring for 10 min, the slurry was filtrated off and the resulting filtrate was concentrated under reduced pressure to give propylene glycol. A flame-dried flask was charged with the obtained

• propylene glycol (26 mg, 0.34 mmol), 4-(dimethylamino)pyridine (8 mg, 0.07 mmol), trimethylamine (70 µL, 0.7 mmol), and CH2Cl2 (3.4 mL). Benzoyl chloride (39 µL, 0.34 mmol) was added dropwise to the solution with stirring. After stirring at room temperature for 25 min, the reaction mixture was poured into

The design and synthesis of an antibacterial phenothiazine–siderophore conjugate

• Abed Tarapdar,
• James K. S. Norris,
• Oliver Sampson,
• Galina Mukamolova and
• James T. Hodgkinson

Beilstein J. Org. Chem. 2018, 14, 2646–2650, doi:10.3762/bjoc.14.242

• -cleavable linker. A polyethylene glycol (PEG) linker was selected as PEG linkers demonstrate enhanced water solubility in comparison to alkyl chain linkers. We then had to make a decision on the position of attachment for the PEG linker to compound 1. For siderophore conjugates, it is crucial that the

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• TTFs. However, also the type of substituent on the TTF moiety plays a role in terms of weak secondary binding interactions such as hydrogen bonds [63]. For example TTF 5 which is substituted by ethylene glycol chains displays a high association constant of Ka = 50,000 M−1 in acetonitrile. Additionally

Efficient catenane synthesis by cucurbit[6]uril-mediated azide–alkyne cycloaddition

• Antony Wing Hung Ng,
• Chi-Chung Yee,
• Kai Wang and
• Ho Yu Au-Yeung

Beilstein J. Org. Chem. 2018, 14, 1846–1853, doi:10.3762/bjoc.14.158

• other topological isomers. The building blocks contain either a central hexaethylene glycol (HEG) unit or are derived from 1,5-dioxynaphthalene (DN), naphthalenediimide (NDI), 2,9-phenanthroline (Phen) or 4,4’-biphenyl (BP) cores which can engage in additional non-covalent interactions, such as metal

• of [3]catenanes The CBAAC-mediated [3]catenane synthesis was first investigated using the dioxynaphthalene building blocks DN-N3 and DN-CC. Different from the previously reported [3]catenane Cat-0 which is derived from DN-N3 and Phen-CC [24], both DN-N3 and DN-CC contain the flexible ethylene glycol

Synthesis of spirocyclic scaffolds using hypervalent iodine reagents

• Fateh V. Singh,
• Priyanka B. Kole,
• Saeesh R. Mangaonkar and
• Samata E. Shetgaonkar

Beilstein J. Org. Chem. 2018, 14, 1778–1805, doi:10.3762/bjoc.14.152

• pathway for the synthesis of the naturally occurring antibiotic platensimycin (154) which is isolated from Streptomyces platensis. In this report, 6-methoxy-1,4-naphthoquinone-4-ethylene ketal (153) was synthesized by intermolecular oxidative cyclization of 7-methoxy-α-naphthol (152) with ethylene glycol

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• electron-poor anilines afford better results than their electron-rich congeners, while a hindered amine (t-BuNH2) completely inhibits the reaction. Shortly after, a similar synthesis of carbazoles involving Cu(OAc)2 as the catalyst in the presence of ethylene glycol both as a ligand and the co-solvent has