Halides as versatile anions in asymmetric anion-binding organocatalysis

• Lukas Schifferer,
• Martin Stinglhamer,
• Kirandeep Kaur and
• Olga García Macheño

Beilstein J. Org. Chem. 2021, 17, 2270–2286, doi:10.3762/bjoc.17.145

• anion coordination and supramolecular chemistry [7][8][9][10][11], this field of research has attracted more attention within the past two decades. Immense efforts were made to identify small molecules that are able to productively bind anions via noncovalent hydrogen bonding, from which cationic

• compounds are coordinated to the H-bond catalyst, whereas anion-binding catalysis relies on the formation of an ion pair by binding to the counter-anion of an ionic substrate. The ionization of the corresponding substrate can either occur before the coordination to the anion or the catalyst itself directly

• design of more efficient H-donor catalyst structures, offering additional noncovalent interactions in order to provide extra coordination points with the anion, substrate and/or reagent. The most important approaches in this direction used to date are presented in the following. (Thio)urea and squaramide

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• aqueous acid solution. Further, the coordination of polymers 37 and 39 to a multinuclear Ru cluster was investigated by the same group [32]. The organometallic complexes 40–43 were synthesized by treating polymers 37 and 39 with Ru3(CO)12 in refluxing xylene (Scheme 9). The ruthenium content in these

• complexes can be varied by changing the ratio of reactants during the reaction. The 1H NMR chemical shift values of the azulene unit were used as a tool to determine the extent of ruthenium coordination to the azulene units in the polymer backbone as the coordinated azulene displays upfield-shifted

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• twentieth most abundant element and the sixth most abundant transition metal in Earth’s crust. Rarely encountered in its metallic form, vanadium exists in oxidation states ranging from +5 to −3, including the four adjacent states +2 to +5 in aqueous solutions, and usually presents 4, 5 or 6 coordination

• manganese is 3d54s2 with a high redox potential due to the high number of available oxidation states (−3 to +7), allowing the formation of compounds with a coordination number of up to 7 [127]. These properties associated with a low toxicity and low cost make manganese a metal with great potential in

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• -carboxamides. The reaction includes oxidative addition of 5-iodo-1,2,3-triazole 117 to a Pd center to achieve the intermediate 120. The intermediate 121 is formed via coordination and insertion of CO to intermediate 120. Then, the intermediate 122 is obtained via a nucleophilic attack of amine 118. Finally, a

Copper-mediated oxidative C−H/N−H activations with alkynes by removable hydrazides

• Feng Xiong,
• Bo Li,
• Chenrui Yang,
• Liang Zou,
• Wenbo Ma,
• Linghui Gu,
• Ruhuai Mei and
• Lutz Ackermann

Beilstein J. Org. Chem. 2021, 17, 1591–1599, doi:10.3762/bjoc.17.113

• observed by parallel experiments, again suggesting that the C‒H activation is kinetically relevant (Scheme 4d). Based on our mechanistic findings and previous studies, we propose a tentative plausible reaction pathway in Scheme 5. The transformation commences with substrate coordination and subsequent

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• expense of the olefin double bond. Review Olefin activation by transition metals Transition metals can act as π-acid catalysts in olefin double bond activation, as they weaken the alkene double bond through coordination to allow a nucleophilic attack on the sp2 carbon to form an alkylmetal intermediate

• , suggesting that the coordination and proton-shuttle ability of the anionic counterion were the main factors responsible for the observed effects. The proposed mechanism (Scheme 10) begins with the activation of the gold(I) pre-catalyst by the exchange of a chloride anion with a non-coordinated one (Y−) to

• suggested that iridium serves as a π-Lewis acid (although one could propose a C–H activation pathway) that activates the olefin by coordination due to the correlation observed between the nature of the Ir counterion and the reaction yields. Radical-based approaches Olefin hydroalkylation via metal hydride

Structural effects of meso-halogenation on porphyrins

• Keith J. Flanagan,
• Maximilian Paradiz Dominguez,
• Zoi Melissari,
• Hans-Georg Eckhardt,
• René M. Williams,
• Dáire Gibbons,
• Caroline Prior,
• Gemma M. Locke,
• Alina Meindl,
• Aoife A. Ryan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2021, 17, 1149–1170, doi:10.3762/bjoc.17.88

• ‘guests’ within the crystal lattice, through hydrogen-bonding and van der Waals forces. Thereafter, research over the crystal engineering of porphyrins has focused on the noncovalent interactions, such as hydrogen bonds and halogen bonds, or metal coordination interactions [2][3][4][5][6][7][8][9][10][11

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

• crystallographic analysis, and it was found that the configuration of the newly generated stereocenter was R. Huang and co-workers proposed a cyclic transition state determined by the coordination of the nitrogen of the imine, and the oxygen atoms of the sulfoxonium and sulfinyl units to the sodium cation, which

Synthesis of multiply fluorinated N-acetyl-D-glucosamine and D-galactosamine analogs via the corresponding deoxyfluorinated glucosazide and galactosazide phenyl thioglycosides

• Vojtěch Hamala,
• Lucie Červenková Šťastná,
• Martin Kurfiřt,
• Petra Cuřínová,
• Martin Dračínský and
• Jindřich Karban

Beilstein J. Org. Chem. 2021, 17, 1086–1095, doi:10.3762/bjoc.17.85

• coordination of ZnI2. When the α-anomer of thioglycoside 17 was separately subjected to the reaction conditions, the byproduct 20 started to form in trace amounts in accordance with the suggested mechanism. The ring contraction may involve formation of a transient oxiranium cation as suggested in Scheme 2 [42

Recent advances in palladium-catalysed asymmetric 1,4–additions of arylboronic acids to conjugated enones and chromones

• Jan Bartáček,
• Jan Svoboda,
• Martin Kocúrik,
• Jaroslav Pochobradský,
• Alexander Čegan,
• Miloš Sedlák and
• Jiří Váňa

Beilstein J. Org. Chem. 2021, 17, 1048–1085, doi:10.3762/bjoc.17.84

• oxidative Heck-type product. The authors stated that as a result of the coordination with PPh3, there is a steric hindrance disfavouring the β-hydride elimination [43]. Catalytic systems based on NHC ligands Historically, the second type of ligands used were N-heterocyclic carbenes (NHC). The first use was

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• -driven research led to a large production of standard every-day drugs with antidiabetic, antiseptic, and even anticancer properties. Recently, biguanides have gained particularly increasing attention in several areas, such as drug design, coordination chemistry, and materials science [1]. In this context

Metal-free glycosylation with glycosyl fluorides in liquid SO₂

• Krista Gulbe,
• Jevgeņija Lugiņina,
• Edijs Jansons,
• Artis Kinens and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 964–976, doi:10.3762/bjoc.17.78

• performed on the model reaction α-11 + MeOH → α-13c to elucidate the influence of SO2 on the dissociation of the glycosidic C–F bond [78] (Figure 2). Indeed, it was found that the coordination of the Lewis acidic SO2 to the fluoride (transition state TS-A≠ versus TS-A(SO2)≠) decreases the C–F bond

Highly regio- and stereoselective phosphinylphosphination of terminal alkynes with tetraphenyldiphosphine monoxide under radical conditions

• Dat Phuc Tran,
• Yuki Sato,
• Yuki Yamamoto,
• Shin-ichi Kawaguchi,
• Shintaro Kodama,
• Akihiro Nomoto and
• Akiya Ogawa

Beilstein J. Org. Chem. 2021, 17, 866–872, doi:10.3762/bjoc.17.72

• compounds in catalytic technologies, biochemistry, and materials [1][2][3][4][5][6]. In particular, in coordination chemistry and catalyst chemistry, organophosphorus compounds such as triorganylphosphines are widely used as typical monodentate ligands for many metals [7][8]. In addition, diphosphines such

• as a monodentate ligand for mononuclear complexes, but it is highly attractive because a hierarchical structure can be constructed by cross-linking between two metals [24][25][26]. Considering the characteristics of the coordination form between the (E)- and (Z)-isomers, the development of a

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

• Shivani Gulati,
• Stephy Elza John and
• Nagula Shankaraiah

Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71

A chromatography-free and aqueous waste-free process for thioamide preparation with Lawesson’s reagent

• Ke Wu,
• Yichen Ling,
• An Ding,
• Liqun Jin,
• Nan Sun,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2021, 17, 805–812, doi:10.3762/bjoc.17.69

• potential large-scale preparations. Thioamides are highly attractive molecules in pharmaceuticals, agrochemicals, electronic chemicals, and materials sciences [17][18][19][20][21][22][23][24][25][26][27]. In coordination chemistry, pincer-type ligands containing a thioamide motif were shown to exhibit

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

• Zhonglie Yang,
• Yutong Liu,
• Kun Cao,
• Xiaobin Zhang,
• Hezhong Jiang and
• Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

• Katritzky alkylpyridinium salt 149 and B2cat2 as substrates as well as DMA as coordination solvent under blue-light irradiation, followed by subsequent reaction with pinacol to afford boration product 151 (Scheme 52). A number of secondary alkylamines, even those that have carbamate- or phthalimide

Synthesis of dibenzosuberenone-based novel polycyclic π-conjugated dihydropyridazines, pyridazines and pyrroles

• Ramazan Koçak and
• Arif Daştan

Beilstein J. Org. Chem. 2021, 17, 719–729, doi:10.3762/bjoc.17.61

• intensity. Although all π-conjugated pyridazines and pyrroles known in the literature did not show high emission, along with other photophysical properties the excellent coordination ability and especially their importance in biological systems always make these compounds valuable. Conclusion Novel

• biochemical studies on these compounds, which have the potential to be used in chemosensors, light harvesting, organic optoelectronics, metal coordination complexes and other photophysical applications and in biological systems. Structures of dibenzosuberenone 1 and pyridazine and pyrrole derivatives

Synthesis, structural characterization, and optical properties of benzo[f]naphtho[2,3-b]phosphoindoles

• Mio Matsumura,
• Takahiro Teramoto,
• Masato Kawakubo,
• Masatoshi Kawahata,
• Yuki Murata,
• Kentaro Yamaguchi,
• Masanobu Uchiyama and
• Shuji Yasuike

Beilstein J. Org. Chem. 2021, 17, 671–677, doi:10.3762/bjoc.17.56

• phosphorus center can be easily chemically modified and converted to phosphole derivatives with different electronic properties by reactions such as oxidation, alkylation, and coordination to a Lewis acid [1][2][3][4][5][6][7][8]. Theoretically, pentacyclic benzonaphthophosphindole contains six structural

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• tpy-containing methanofullerene dyads 184–186, coordination of which with ruthenium(II) gives donor–bridge–acceptor assemblies 187–189. Synthesis of a series of spirocyclopentalydenemethanofullerenes 190–193. Synthesis of spiromethanofullerenes 194 and 195. The synthetic route to ring-B-C60-attached

Amino- and polyaminophthalazin-1(2H)-ones: synthesis, coordination properties, and biological activity

• Zbigniew Malinowski,
• Emilia Fornal,
• Agata Sumara,
• Renata Kontek,
• Karol Bukowski,
• Beata Pasternak,
• Dariusz Sroczyński,
• Joachim Kusz,
• Magdalena Małecka and
• Monika Nowak

Beilstein J. Org. Chem. 2021, 17, 558–568, doi:10.3762/bjoc.17.50

• the coordination of the amine takes place after the oxidative addition of the organic halide to the palladium–ligand complex. Based on the analysis of our results we have concluded that in the case of systems 3, the order of reagent addition could have a significant impact on a proper course of the

• 77% yield. Moreover, it turned out that this amination reaction also proceeded with a reduced amount of Pd2(dba)3 from 15 mol % to 2 mol % without loss of the product yield. These results showed that the coordination of the amine to the (BINAP)Pd complex probably leads to the formation of a (BINAP)Pd

• behavior of aminophthalazinones with Cu(II) ions To conclude the synthetic research, we looked at the potential of aminophthalazinones as polydentate ligands for the synthesis of complexes with metal ions. Examples of the use of phthalazinone and its derivatives in the synthesis of coordination compounds

Metal-free visible-light-enabled vicinal trifluoromethyl dithiolation of unactivated alkenes

• Xiaojuan Li,
• Qiang Zhang,
• Weigang Zhang,
• Jinzhu Ma,
• Yi Wang and
• Yi Pan

Beilstein J. Org. Chem. 2021, 17, 551–557, doi:10.3762/bjoc.17.49

• Xiaojuan Li Qiang Zhang Weigang Zhang Jinzhu Ma Yi Wang Yi Pan State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, and Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University

Annulation of a 1,3-dithiole ring to a sterically hindered o-quinone core. Novel ditopic redox-active ligands

• Sergey V. Norkov,
• Anton V. Cherkasov,
• Andrey S. Shavyrin,
• Maxim V. Arsenyev,
• Viacheslav A. Kuropatov and
• Vladimir K. Cherkasov

Beilstein J. Org. Chem. 2021, 17, 273–282, doi:10.3762/bjoc.17.26

• State University, 23 Gagarin Ave, 603950, Nizhny Novgorod, Russia 10.3762/bjoc.17.26 Abstract The fused 1,3-dithiole spacer seems to be very suitable for the functionalization of sterically hindered o-quinones with additional groups capable of coordination of metal ions and/or possessing a redox

• ligand; 1,3-dithiole; ditopic ligand; o-quinone; thiete; Introduction There are a number of methods which may be used for the synthesis of new o-quinones in order to vary their redox properties and coordination abilities. The key features of o-quinones are redox activity as well as chelating

• coordination ability. The redox state of o-quinone (semiquinone or catechol) could be changed both as free species or when it is coordinated to a metal ion as a ligand. Thus, the redox isomerism phenomenon was reported for o-quinone complexes with both transition and non-transition metals [1][2][3]. The

Au(III) complexes with tetradentate-cyclam-based ligands

• Ann Christin Reiersølmoen,
• Thomas N. Solvi and
• Anne Fiksdahl

Beilstein J. Org. Chem. 2021, 17, 186–192, doi:10.3762/bjoc.17.18

• -membered chelate rings. The testing of the catalytic ability of the cyclam-based N,N,N,N-Au(III) complexes demonstrated high catalytic activity of some complexes in selected test reactions (full conversion in 1–24 h, 62–97% product yields). Keywords: Au(III); carboalkoxylation; coordination studies

• ]. In contrast, gold(III) catalysis was for a long time mostly based on inorganic salts, such as AuCl3, AuBr3, or pyridine–AuCl3 and Pic–AuCl2. However, Au(III) complexes with various coordinated ligands are about to become more explored. Different from the linear coordination mode of gold(I), gold(III

• ) forms square planar complexes. This allows for greater steric control around the reaction center by using polydentate ligands. An interesting group of ligands which may coordinate to all the four coordination sites of gold(III), are represented by polyamine ligands, such as cyclam (1,4,8,11

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

• different Ti–S coordination modes between H4TC4A–Ti4 and H4TC4A–Ti6 result in different photocatalytic activities. The H2 evolution of H4TC4A–Ti4 was almost 5 times that of H4TC4A–Ti6 (73.56 μmol⋅g−1⋅h−1 vs 15.16 μmol⋅g−1⋅h−1). This work emphasized the importance of structure–efficiency relationships of

Molecular basis for protein–protein interactions

• Brandon Charles Seychell and
• Tobias Beck

Beilstein J. Org. Chem. 2021, 17, 1–10, doi:10.3762/bjoc.17.1

• containers in vitro. These highly charged variants were then used to form a binary three-dimensional assembly analogous to inorganic salts. The structure of this assembly was determined to have a 1:1 stoichiometry, with a coordination number of 12. The advantage of such systems was discussed to be that each