Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

• anthraquinone moiety to give synthetic Cellulose I [94]. Overall, enzymatic synthesis is an established procedure to obtain non-uniform cellulose oligo- and polysaccharides. Some success was achieved using additives and molecular crowding conditions; however, this approach remains limited by product

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

• have been used as additives in these reactions and are suggested to act as ligands, assist proton transfer and promote the formation of oligovanadates by decreasing the pH value of the solution. The mechanisms of some vanadium-mediated oxidation reactions of alkanes have been studied, most of them

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

• (acetylacetonate) in the cross-coupling cycle. They achieved the desired cross-coupling products 89 with the reaction conducted in open air and under mild conditions (Scheme 35) [109]. Notably, the use of propylene carbonate as the co-solvent removed the need for inclusion of reductant or oxidant additives, such

Recent advances in the application of isoindigo derivatives in materials chemistry

• Andrei V. Bogdanov and
• Vladimir F. Mironov

Beilstein J. Org. Chem. 2021, 17, 1533–1564, doi:10.3762/bjoc.17.111

• existing polymer conductive binder mixed with carbon additives (Scheme 31). Isoindigo derivatives have begun to find use in biomedical applications. Thus, nanoparticles of isoindigoid polymers have shown good potential as agents for photoacoustic and photothermal cancer therapy [116][117][118][119][120

• electron donor/acceptor nature, the heterocyclic substituents, and the branching of the alkyl radical at the endocyclic nitrogen atom. Research on methods to obtain polymer isoindigo thin films and the use of additives will, in our opinion, significantly improve the efficiency of materials. In addition

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

• for the water removal instead employed either DMSO or ionic liquids as additives for the water removal. The same condensation (of 17 to 127) was also performed by Clark et al. using a silica-coated microreactor with an AP-T catalyst deposited on the reactor’s walls [160]. The solvent-free approach

Heterogeneous photocatalytic cyanomethylarylation of alkenes with acetonitrile: synthesis of diverse nitrogenous heterocyclic compounds

• Guanglong Pan,
• Qian Yang,
• Wentao Wang,
• Yurong Tang and
• Yunfei Cai

Beilstein J. Org. Chem. 2021, 17, 1171–1180, doi:10.3762/bjoc.17.89

• cyanomethylarylation of alkenes, most of them rely on the use of transition metals (such as catalytic amounts of Pd, Cu, Fe catalyst or stoichiometric amounts of Ag, Mn salts) and strong oxidants (including PhI(OPiv)2, DTBP, and t-BuONO) in the presence of various base additives under high reaction temperatures or

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

• reactions using organolithium and organocerium compounds. In some examples, the use of organolithium is feasible through the use of aluminum-derived additives [15]. In this study, the influence of solvents on diastereoselectivity was also observed. They found that the reactions performed in noncoordinating

• solvent, metal and additives in 1,2-addition reactions to N-tert-butanesulfinyl imines of organometallic compounds, different transition models have been proposed to explain the stereochemical outcomes. The cyclic model justified by the Zimmermann–Traxler transition state [40][41][42] is the typical

• t-BuOH and LiBr as additives [102]. The isopropyl-substituted derivative 84 was easily converted into the corresponding methylene lactam 85, upon removal of the sulfinyl unit under acidic conditions. Finally, ozonolysis of 85 yielded tetramic acid 86 in 60% yield (Scheme 26). The configuration of

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

• suitability of the ligand used, the reaction conditions, and additives in terms of the yield and enantioselectivity of the transformation have been discussed. The review is classified according to the type of ligand of the catalytic complex used. The yields and corresponding enantioselectivities from the

Synthesis of 10-O-aryl-substituted berberine derivatives by Chan–Evans–Lam coupling and investigation of their DNA-binding properties

• Peter Jonas Wickhorst,
• Mathilda Blachnik,
• Denisa Lagumdzija and
• Heiko Ihmels

Beilstein J. Org. Chem. 2021, 17, 991–1000, doi:10.3762/bjoc.17.81

• ). Further attempts to optimize the reaction conditions showed that the reaction mostly led to decomposition of the starting material in polar protic solvents or in the presence of bases or additives other than triethylamine (cf. Supporting Information File 1). However, the product was isolated in a moderate

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

• , often heavy metals; (2) multiple additives (co-promoter, molecular sieves, acid scavenger) to facilitate the reaction and/or suppress formation of side-products; (3) low temperatures; (4) complex experimental procedures. Additionally, the majority of the methods reported to date have been applied only

• the yield of mannoside 3b formed from a less reactive secondary alcohol 2b, various additives were tested (Table 1, entries 7–9). Presence of basic molecular sieves (4 Å) as a drying agent led to lower yield and did not suppress the formation of hemiacetal α-4 (Table 1, entry 7), while no reaction was

• observed when additives containing a fluorophilic silicon center were used (Table 1, entries 8 and 9). The inhibitory effect of basic molecular sieves may point to the presence and contributory role of protic acid (HF or H2SO3) in the course of the reaction [64]. Whereas, silyl additives can react with

Manganese/bipyridine-catalyzed non-directed C(sp³)–H bromination using NBS and TMSN₃

• Kumar Sneh,
• Takeru Torigoe and
• Yoichiro Kuninobu

Beilstein J. Org. Chem. 2021, 17, 885–890, doi:10.3762/bjoc.17.74

• benzylic positions of a wide range of substrates. The manganese catalyst, brominating agent, and additives are commercially available, and the reaction can be achieved by simply mixing these reagents with the substrate. Results and Discussion The reaction of isoamyl alcohol derivative 1a with N

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

• excellent yields. Results and Discussion Our initial exploration began with the thio-substitution of N-phenylbenzamide (1a) with LR in toluene at reflux (Table 1). After completing the reaction, the solutions were split and treated with different additives at various temperatures in order to identify a

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

• electrons from the electron-rich tertiary amine nitrogen atom to the electron-deficient benzene ring, achieving intramolecular electron transfer. Selective C–H-functionalization also includes no catalysts, oxidants, additives, acids and bases, which is of great significance in the synthesis and application

• additives at 50 °C and under irradiation with light (Scheme 32). The reaction is compatible with phenyl substituents with high steric hindrance, indicating that steric effects of the aryl moiety in the migrating styrenyl group do not play a major role. In 2018, You and colleagues [19] reported the discovery

[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

• alternatives that favorably differ in cost. However, the efficiency is similar to the functional analogs of catalytic additives based on noble metals [52]. The presence of metal–fullerene chemical bonding results in catalysts that reliably provide high process selectivity due to the simultaneous adsorption of

Valorisation of plastic waste via metal-catalysed depolymerisation

• Francesca Liguori,
• Carmen Moreno-Marrodán and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

• purification steps, the addition of additives or blending with fresh polymers may be included [48]. For this reason, both reextrusion and physical recycling are also referred to as “mechanical recycling”, primary and secondary, respectively [49][50]. However, materials of lower quality and economic value can

• be resistant to the presence of contaminants and impurities (e.g., additives, pigments) [188]. More recently, effective PET depolymerisation was accomplished by a ruthenium molecular catalysts bearing the well-known tripodal phosphorous ligand 1,1,1-tri(diphenylphosphinomethyl)ethane (triphos) [189

• of 6 equiv of 1,1,3,3-tetramethyldisiloxane (TMDS) led to the total conversion to propane and polydimethylsiloxane (PDMS), a silicon oil with several applications (lubricants, food-additives, breast implants). 3.2.3 Other polyesters: The hydrogenolysis reaction of esters other than PET and PLA was

Deoxygenative C2-heteroarylation of quinoline N-oxides: facile access to α-triazolylquinolines

• Geetanjali S. Sontakke,
• Rahul K. Shukla and
• Chandra M. R. Volla

Beilstein J. Org. Chem. 2021, 17, 485–493, doi:10.3762/bjoc.17.42

• pyridine N-oxides [54]. Despite the versatility of these methods, the above reports involve the use of external additives for activating the N-oxides and suffer from other disadvantages, including prolonged reaction time, high temperature and limited substrate scope. At the same time, with the advent of Cu

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

• showed no interaction with Au(III), as expected. A similar resistance to coordinate was observed for the open diamides 1c–e. The phosphorus containing ligand 1c did undergo phosphorus oxidation instead of Au(III) coordination. No effect was obtained by refluxing or by adding additives, such as silver

Regioselective synthesis of heterocyclic N-sulfonyl amidines from heteroaromatic thioamides and sulfonyl azides

• Vladimir Ilkin,
• Vera Berseneva,
• Tetyana Beryozkina,
• Tatiana Glukhareva,
• Lidia Dianova,
• Wim Dehaen,
• Eugenia Seliverstova and
• Vasiliy Bakulev

Beilstein J. Org. Chem. 2020, 16, 2937–2947, doi:10.3762/bjoc.16.243

• various additives (Table 2). We have shown that optimal conditions include the use of n-propanol, a temperature of 97 °C and a ratio of thioamide 1j and azide 2c of 1:7 which allowed to prepare the desired compound 3t in 78% (Table 2). With the optimal conditions in hand we prepared a series of N-sulfonyl

A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles

• Bingbing Lai,
• Meng Ye,
• Ping Liu,
• Minghao Li,
• Rongxian Bai and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2888–2902, doi:10.3762/bjoc.16.238

• exhibited low catalytic efficiencies in the model reaction, only 60% and 48% of 7a were obtained, respectively (Table 2, entries 9 and 10). The results indicated that the yields were also greatly affected by the catalyst loading and proper acid additives. In the same solvent, the yield decreased with the

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

• ingredients in a lot of technical applications. They can act as a flotation agent in the enrichment of ores [1], emulsifier and stabilizer for emulsions [2], or as additives for self-cleaning surfaces (artificial lotus effect) [3][4]. Rhamnolipids (RL, Figure 1) are biosurfactants, that are produced by

• described by Leisinger et al. [9]. Rhamnolipids possess some advantages, that make them interesting candidates as cleaning agents or additives for care applications in the consumer goods industry. They can be produced in a fermentation process from renewable nontropic material [10][11]. RL are also

Asymmetric Mannich reactions of (S)-N-tert-butylsulfinyl-3,3,3-trifluoroacetaldimines with yne nucleophiles

• Ziyi Li,
• Li Wang,
• Yunqi Huang,
• Haibo Mei,
• Hiroyuki Konno,
• Hiroki Moriwaki,
• Vadim A. Soloshonok and
• Jianlin Han

Beilstein J. Org. Chem. 2020, 16, 2671–2678, doi:10.3762/bjoc.16.217

• the completion of this transformation (Table 1, entries 11 and 12). Finally, we found that the use of Lewis acids BF3·Et2O and Ti(OiPr)4 as additives for this reaction was unsuccessful and the same level of chemical yield and diastereoselectivity was observed (Table 1, entries 13 and 14). With the

Particle size effect in the mechanically assisted synthesis of β-cyclodextrin mesitylene sulfonate

• Stéphane Menuel,
• Sébastien Saitzek,
• Eric Monflier and
• Frédéric Hapiot

Beilstein J. Org. Chem. 2020, 16, 2598–2606, doi:10.3762/bjoc.16.211

• bioavailability [11][12][13]. In our previous studies, CDs acted either as reactants [14][15], or as additives [16][17], and were shown to display supramolecular interactions with the other reaction partners. We demonstrated that the formation of CD/substrate supramolecular complexes favored the dispersion of the

Synthesis of 1,4-benzothiazinones from acylpyruvic acids or furan-2,3-diones and o-aminothiophenol

• Ekaterina E. Stepanova,
• Maksim V. Dmitriev and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2020, 16, 2322–2331, doi:10.3762/bjoc.16.193

• acids or their esters IV with o-aminothiophenol (1a) to afford the target BTAs III can be explained both by the impossibility of thioesterification/thiotransesterification to proceed under additives-free conditions and by the high nucleophilicity of the o-aminothiophenol’s SH group that attacked the

• additives for carbodiimide coupling reactions, DMAP [30] and HOBt [31]. The utilization of HOBt (Table 1, entries 25 and 26) in acetonitrile as an additive did not significantly influence the yield of BTA 3a. But since the solubility of HOBt in acetonitrile is poor [32], we examined the reaction in DMF and

Chan–Evans–Lam N1-(het)arylation and N1-alkеnylation of 4-fluoroalkylpyrimidin-2(1H)-ones

• Viktor M. Tkachuk,
• Oleh O. Lukianov,
• Mykhailo V. Vovk,
• Isabelle Gillaizeau and
• Volodymyr A. Sukach

Beilstein J. Org. Chem. 2020, 16, 2304–2313, doi:10.3762/bjoc.16.191

• acid (2a). Effect of boric acid and pyridine additives on the Chan–Evans–Lam reaction of 4-trifluoromethylpyrimidin-2(1H)-one (1а) with phenylboronic acid pinacol ester (6а). Supporting Information Supporting Information File 468: Experimental procedures, characterization data, copies of the 1H and

Stereoselective Biginelli-like reaction catalyzed by a chiral phosphoric acid bearing two hydroxy groups

• Xiaoyun Hu,
• Jianxin Guo,
• Cui Wang,
• Rui Zhang and
• Victor Borovkov

Beilstein J. Org. Chem. 2020, 16, 1875–1880, doi:10.3762/bjoc.16.155

• solvent screening showed that the target product could be obtained in 95% ee catalyzed by 3 in CHCl3 (Table 1, entry 4). However, acidic and basic additives [23][24] resulted in a decrease of the enantioselectivity (Table 1, entries 10–12), or even to racemization in the case of TFA (Table 1, entry 13

• explains that more polar or protic solvents and strong acidic additives also destroyed the H-bondings resulting in decreased enantioselectivities or even racemization (Table 1, entries 7 and 13). Conclusion In summary, a new phosphoric acid bearing two free hydroxy groups was synthesized based on a highly