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

• homogeneous catalysts (Scheme 7). Significantly, IL catalysts 47b,c could be extracted from the reaction mixture for six consecutive cycles. In all runs, IL catalysts 47b,c showed excellent catalytic activity. The FTIR spectra of two of these reused ILs after the 6th run and the fresh ILs have been used to

• prove the retention of their catalytic activity [46]. Khazaei et al. prepared 3-methyl-1-sulfo-1H-imidazolium tetrachloroferrate ([Msim]FeCl4, 3) as a nanostructured catalyst via the reaction of 3-methyl-1-sulfon-1H-imidazolium chloride with dry FeCl3. After stirring the starting materials for 60

• products from the catalyst. The catalyst showed good catalytic activity for four successive runs [47]. Tayebee and co-workers prepared 3-sulfo-imidazolopyridinium hydrogen sulfate ([Simp]HSO4, 53) as a new natural ionic liquid by the reaction between caffeine (51) as a natural, inexpensive, and available

Photocatalyic Appel reaction enabled by copper-based complexes in continuous flow

• Clémentine Minozzi,
• Jean-Christophe Grenier-Petel,
• Shawn Parisien-Collette and
• Shawn K. Collins

Beilstein J. Org. Chem. 2018, 14, 2730–2736, doi:10.3762/bjoc.14.251

• conversion of an alcohol to bromide involved screening a wide variety of structurally varied complexes. Our group has previously demonstrated that the nature of each ligand influences the physical and photophysical properties as well as catalytic activity of the resulting catalyst (Figure 2) [27]. A library

Transition metal-free oxidative and deoxygenative C–H/C–Li cross-couplings of 2H-imidazole 1-oxides with carboranyl lithium as an efficient synthetic approach to azaheterocyclic carboranes

• Lidia A. Smyshliaeva,
• Mikhail V. Varaksin,
• Pavel A. Slepukhin,
• Oleg N. Chupakhin and
• Valery N. Charushin

Beilstein J. Org. Chem. 2018, 14, 2618–2626, doi:10.3762/bjoc.14.240

• capture therapy (BNCT) of cancer [8][9][10][11][12], as well as agonists and antagonists of biological receptors [13][14][15][16][17], etc. In addition, azaheterocyclic carboranes are actively used as ligands in the synthesis of metal complexes of various architectures, possessing catalytic activity [18

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

• terms of both catalytic activity and visible-light harvesting. In relation to the reactivity of 1 with DDT, interesting reactions of trichlorinated organic compounds have recently been investigated [100][114]. The B12-TiO2 hybrid catalyst converted trichlorinated organic compounds into esters and amides

• use of vitamin B12 [116]. Furthermore, cobalester, an amphiphilic vitamin B12 derivative with six ester groups and a nucleotide loop, has recently been developed to show good catalytic activity for C–C bond forming reactions [117][118]. The above-mentioned visible-light-driven system composed of 1

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

• expanded the “low-oxidation-state route” to the synthesis of 2,4,6-trimethylbenzylidyne complexes of molybdenum and tungsten [18][49][50], which led to an increased steric demand at the metal center. This proved to be advantageous for the catalytic activity, since the removal of coordinating solvents like

• studies With the bimetallic complexes Mo2F6 and W2F3 and the new alkylidyne complex WPhF3 at hand, we aimed at systematically investigating the catalytic activity of those complexes. Even though we failed in selectively cleaving the Mo≡Mo triple bond, we attempted catalytic alkyne metathesis with Mo2F6

• . Interestingly, a marginal catalytic activity could be detected for complex Mo2F6: over the course of four days, the dimolybdenum complex achieved a conversion of 70% in the self-metathesis of the standard substrate 3-pentynyl benzyl ether in toluene in the presence of molecular sieves (MS 5 Å) as 2-butyne

Cationic cobalt-catalyzed [1,3]-rearrangement of N-alkoxycarbonyloxyanilines

• Itaru Nakamura,
• Mao Owada,
• Takeru Jo and
• Masahiro Terada

Beilstein J. Org. Chem. 2018, 14, 1972–1979, doi:10.3762/bjoc.14.172

• 1,3-bis(diphenylphosphino)propane (dppp), totally diminished the activity of cationic cobalt catalyst (Table 1, entries 6 and 7). Among metal chlorides examined, CoCl2 exhibited the best catalytic activity at 30 °C, affording the corresponding 2a in 68% yield (Table 1, entry 9), as reported previously

• , entry 20), the catalytic activity was diminished at 30 °C (Table 1, entry 21). Neutral CoCl2 did not promote the present reaction (Table 1, entry 22). Brønsted acids, such as trifluoromethanesulfonic acid and diphenylphosphoric acid, were much less active (Table 1, entries 23 and 24). The kind of the

• :1) as eluent to obtain 2k (113.9 mg, 82%). ortho-Aminophenol derivatives. Rearrangement of N-acyloxyanilines. Mechanistic studies, reported in [13]. Competitive experiments, reported in [13]. Mechanism for rearrangement to the para-position. Catalytic activity. Solvent and concentration effects

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

• their SCS analogues, SNS pincer complexes are poorly studied for their use in coupling reactions. Accordingly, a series of water soluble cationic Pd(II) SNS pincer complexes have been successfully synthesised and investigated in detail for their catalytic activity in Suzuki–Miyaura coupling reactions

• inactivated aryl bromides according to the study conducted by Bai and Hor [34]. Similarly, Kumar et al. studied the catalytic activity of pincer complex 16 and reported that the catalyst was compatible with activated aryl bromides to provide reasonable yields over 12 h at 100 °C using 2 mol % catalyst loading

• investigation of their catalytic activity in the aqueous Suzuki–Miyaura coupling reaction. Herein, we report the synthesis of the SNS Pd(II) pincer complexes and their interesting catalytic activities in the Suzuki–Miyaura cross coupling reactions in neat water. Results and Discussion Our study commenced with

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

• Brønsted and Lewis acid and base catalysis. Pizzo and co-workers conducted a comparative study on the catalytic activity of Lewis and Brønsted acids as well as bases for the thiolysis of epoxides using InCl3, p-TsOH, n-Bu3P and K2CO3 as representative examples, respectively. Although all of them effected

• organophosphine was found to have a profound effect on the catalytic activity; some reactions were sluggish when tricyclohexylphosphine or triphenylphosphine were used as catalysts. The tributylphosphine acts as a nucleophilic trigger to attack, and thus initiates the reaction. 3.1.1.3 Use of zinc salts. In

Spectroelectrochemical studies on the effect of cations in the alkaline glycerol oxidation reaction over carbon nanotube-supported Pd nanoparticles

• Dennis Hiltrop,
• Steffen Cychy,
• Karina Elumeeva,
• Wolfgang Schuhmann and
• Martin Muhler

Beilstein J. Org. Chem. 2018, 14, 1428–1435, doi:10.3762/bjoc.14.120

• (Ep1 and Ep2) are found at lower anodic potentials (−29 and −52 mV vs RHE on average) compared with Pd/OCNT. Although the peak current densities are almost equal, the catalytic activity towards glycerol oxidation is higher for Pd/NCNT, as the reaction starts at lower anodic overpotentials. This

• structural properties of the catalyst, whereas the changes in jp1 and jp2 are caused by the nature of the cation in the electrolyte. The higher catalytic activity of the metallic Pd NPs supported on NCNTs in heterogeneous gas-phase catalysis has been explained by an electronic effect due to the electron

Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• important role in the catalytic activity and the selectivity. In addition, the catalytic performance of 7 was found sensitive to the cation of the base. Because, when aqueous NaOH was used instead of KOH, a higher yield and ee were obtained. It is proposed that a better chelating ability of 7 toward the

• product 5a in 86% yield up to 35% ee (Scheme 4). In order to assess the effect of the calixarene backbone on the catalytic activity and enantioselectivity, they also performed the reaction in the presence of a chiral monoamide and an achiral calix[4]arene-tetramide. The results obtained in the presence of

• asymmetric Tsuji–Trost allylic alkylation of 1,3-diphenylprop-2-enyl acetate (33) with dimethyl malonate (34, Scheme 9). Both, good catalytic activity and enantioselectivity (ee values up to 86%) were obtained with the potassium cation. This was due to the more strongly interaction of the dimethyl malonate

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

• guanidinium compound. This low basicity was suggested to be a central factor behind the catalytic activity. A clarification of the mechanism of guanidine-based catalysis has more recently been attempted by anchoring a 2,4-diamino-1,3,5-triazine core to the N3 of uracil bases of UpU by two side arms, each

• hydroxy function on phosphorus (Scheme 8). Similar results were obtained on using diphenylmethane as a scaffold 8 (Figure 8) [81]. A cyclohexylidene or adamantylidene substituent on the methylene carbon moderately enhanced the catalytic activity. Interestingly, the calix[4]arene-based agent 7 catalyzed

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• is occurring in the lipophilic pocket and not in water. The authors also demonstrated the ability of the PQS system to be recycled up to 10 times without loss in its catalytic activity. Catalytic micelles were also prepared by O’Reilly et al. when a novel amphiphilic Sulfur–Carbon–Sulfur (SCS) pincer

• Pd catalyst together with a PAA (poly(acrylic acid)) based polymer self-assembled in water [32]. The catalytic activity of the nanostructures was compared to the results achieved with the small molecule analogues of the pincer Pd complex, in a Suzuki–Miyaura coupling. When the reaction of vinyl

• -coupling reactions. Catalytic activity was compared to the activity of the freshly prepared free catalyst, and the palladium entrapment did not affect either the conversion or the yields of the reaction [28]. The catalyst immobilization also allowed facile Pd removal from the final product and catalyst

Cobalt-catalyzed directed C–H alkenylation of pivalophenone N–H imine with alkenyl phosphates

• Wengang Xu and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2018, 14, 709–715, doi:10.3762/bjoc.14.60

• Grignard reagent would furnish the alkenylation product 3·MgX and regenerate the species A. While the relationship between the ligand and the catalytic activity remains unclear, we speculate that a strong σ-donating ability of NHC ligands would facilitate the SET step among others. Conclusion In summary

Heterogeneous Pd catalysts as emulsifiers in Pickering emulsions for integrated multistep synthesis in flow chemistry

• Katharina Hiebler,
• Georg J. Lichtenegger,
• Manuel C. Maier,
• Eun Sung Park,
• Renie Gonzales-Groom,
• Bernard P. Binks and
• Heidrun Gruber-Woelfler

Beilstein J. Org. Chem. 2018, 14, 648–658, doi:10.3762/bjoc.14.52

• for catalysts rich in tin. Suzuki–Miyaura coupling reactions Batch reactions The catalytic activity of the synthesised catalysts in the Suzuki–Miyaura reaction was investigated using phenylboronic acid 3 in combination with various bromoarenes 4a–e, featuring ortho- and para-substitution of electron

• reach full conversion. p-Bromobenzenes containing electron-withdrawing substituents showed higher reactivity than bromobenzenes containing electron-donating groups. When Ce0.495Sn0.495Pd0.01O2–δ was employed as catalyst, however, the catalytic activity was found to be significantly lower and the binary

• connected to their catalytic activity. Nevertheless, there are indications that the surface area and the particle size distribution play a role in the catalytic performance of the palladium substituted metal oxides. In view of the aimed application of the Pd metal oxides for targeted API synthesis, the

An air-stable bisboron complex: a practical bidentate Lewis acid catalyst

• Longcheng Hong,
• Sebastian Ahles,
• Andreas H. Heindl,
• Gastelle Tiétcha,
• Andrey Petrov,
• Zhenpin Lu,
• Christian Logemann and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2018, 14, 618–625, doi:10.3762/bjoc.14.48

• enhancing its practicality. Comparative reactions were carried out to evaluate its catalytic activity in IEDDA reactions of diazine including phthalazine as well as 1,2,4,5-tetrazine. Keywords: air-stable catalyst; bidentate; bisboron; diazine; Diels–Alder; Lewis acid; Introduction The development of

• reactions were carried out and the results showed that the catalytic activity of the complex in IEDDA reactions depended on its performance in ligand exchange with the diazine substrates. Experimental Complexation of 5,10-dimethyl-5,10-dihydroboranthrene with Lewis bases: In the glovebox, 5,10-dimethyl-5,10

Addition of dithi(ol)anylium tetrafluoroborates to α,β-unsaturated ketones

• Yu-Chieh Huang,
• An Nguyen,
• Simone Gräßle,
• Sylvia Vanderheiden,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2018, 14, 515–522, doi:10.3762/bjoc.14.37

• completion within 3 hours if 10% of HBF4 remains in the reaction mixture (see table for comparative experiments in the Supporting Information File 1). This result indicates the catalytic activity of HBF4 in the reaction. The same product 4c can be obtained if an isolated ketene dithi(ol)ane is subjected to

Carbohydrate inhibitors of cholera toxin

• Vajinder Kumar and
• W. Bruce Turnbull

Beilstein J. Org. Chem. 2018, 14, 484–498, doi:10.3762/bjoc.14.34

• pentamer of B-subunits [5]. The catalytic activity of the toxins is due to the A-subunit, while the B-subunit enables binding of the complex to the cell surface and its delivery into the target cells, hence the complete AB5 holotoxin is required for their toxic effects. Because of the difference in the

• sequence homology and catalytic activity, the classes of AB5 toxins are subdivided into three families (Figure 3): the cholera toxin (CT) family, the shiga toxin (ST) family and the pertussis toxin (PT) family [6]. The CT family contains CT, and heat-labile toxins LT-I and LT-II [7][8]. The ST family

Stimuli-responsive oligonucleotides in prodrug-based approaches for gene silencing

• Françoise Debart,
• Christelle Dupouy and
• Jean-Jacques Vasseur

Beilstein J. Org. Chem. 2018, 14, 436–469, doi:10.3762/bjoc.14.32

• ][75][76], and occasionally for RNA-cleaving activity with DNAzymes [77]. It is expected that phosphate-modified siRNAs sterically block the interaction of siRNA with the RISC complex and that the process is turned on upon photoirradiation [72]. Considering DNAzymes, their catalytic activity is

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• (Scheme 42b) [79]. The catalyst was recycled and reused after centrifugation and washing with ethanol. High catalytic activity was preserved for at least 3 cycles. Very recently, the group of Zhang published a photocatalyzed procedure for the preparation of β-acetylaminoacrylsulfones from the respective

Synthetic mRNA capping

• Fabian Muttach,
• Nils Muthmann and
• Andrea Rentmeister

Beilstein J. Org. Chem. 2017, 13, 2819–2832, doi:10.3762/bjoc.13.274

• -terminal half and the methyltransferase in the C-terminal half of the large D1 protein, whereas the small D12 protein has no catalytic activity but activates D1 [36][37][38]. Originally, the RNA capping with the Vaccinia capping apparatus was reported to be inefficient [35][37][39][40]. To date, the enzyme

Sulfation and amidinohydrolysis in the biosynthesis of giant linear polyenes

• Hui Hong,
• Markiyan Samborskyy,
• Katsiaryna Usachova,
• Katharina Schnatz and
• Peter F. Leadlay

Beilstein J. Org. Chem. 2017, 13, 2408–2415, doi:10.3762/bjoc.13.238

• of the assembly-line PKS in both clethramycin and mediomycin biosynthesis. The sulfotransferases from the cle and med clusters appear essentially identical in their catalytic activity. The co-location of the slf gene with the gigantic 27-extension module PKS of clethramycin or mediomycin suggested

Is the tungsten(IV) complex (NEt₄)₂[WO(mnt)₂] a functional analogue of acetylene hydratase?

• Matthias Schreyer and
• Lukas Hintermann

Beilstein J. Org. Chem. 2017, 13, 2332–2339, doi:10.3762/bjoc.13.230

• , ionization is brought about without an added reagent, and catalytic activity towards Markovnikov product 5 revealed, even if the conversion is low (Table 1, entry 1). A cyclopentadienylruthenium(II) catalyst with the ambifunctional steering ligand ISIPHOS (2-(diphenylphosphino)-6-(2,4,6-triisopropylphenyl

• catalytic activity by increasing conversion to higher levels through increasing the catalyst loading [36]. Tests of complex 1 with purified 4 in acetone–water or acetonitrile–water failed to show catalytic activity (Table 1, entries 6 and 7). The recovery of 4 was excellent (97–98%) and the side products

• 3 cannot be excluded. Continued interest in functional models of acetylene hydratase [14][15][16][42] and a theoretical study on the mechanisms of acetylene hydration by complex 1 [17] have motivated us to scrutinize the claimed biomimetic catalytic activity by performing the hydration experiment

Transition-metal-free synthesis of 3-sulfenylated chromones via KIO₃-catalyzed radical C(sp²)–H sulfenylation

• Yanhui Guo,
• Shanshan Zhong,
• Li Wei and
• Jie-Ping Wan

Beilstein J. Org. Chem. 2017, 13, 2017–2022, doi:10.3762/bjoc.13.199

• as KI, I2 or KIO3 could all catalyze the domino reaction to provide product 3a, wherein KIO3 displayed the highest catalytic activity (entries 2–4, Table 1). On the other hand, in the reactions performed in different media, including DMSO, ethyl lactate (EL), EtOH, MeCN, 1,4-dioxane and toluene, DMF

New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions

• Daily Rodríguez-Padrón,
• Alina M. Balu,
• Antonio A. Romero and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1982–1993, doi:10.3762/bjoc.13.194

• potential from an environmental point-of-view since it is able to reduce solvent issues in chemical syntheses. The catalytic activity of the obtained nanocatalysts was investigated in both the oxidation of benzyl alcohol to benzaldehyde and in the alkylation of toluene with benzyl chloride. The microwave

• oxide–iron oxide–polysaccharide 4 (TiO2-Fe2O3-PS4) nanocomposites. The materials were successfully obtained using the proposed solvent-free methodology, which is depicted in Figure 1. The materials were characterized by the techniques presented below. The catalytic activity of these systems has been

• material. Such values make this a material with attractive feature for magnetic separation (Table 4) [40]. Catalytic activity The catalytic activity of these materials has been investigated in two reactions: 1) the oxidation of benzyl alcohol to benzaldehyde and the 2) alkylation of toluene with benzyl