Cobalt-catalyzed C–H cyanations: Insights into the reaction mechanism and the role of London dispersion

• Eric Detmar,
• Valentin Müller,
• Daniel Zell,
• Lutz Ackermann and
• Martin Breugst

Beilstein J. Org. Chem. 2018, 14, 1537–1545, doi:10.3762/bjoc.14.130

• numerical quadrature grid in the gas phase. The hybrid functional B3LYP [53][54] with and without Grimme’s dispersion correction D3 (Becke–Johnson damping) [35][36] as well as Truhlar’s dispersion-corrected M06-L [55] functional were employed in this investigation. For the latter, the density fitting RI-J

Mild and selective reduction of aldehydes utilising sodium dithionite under flow conditions

• Nicole C. Neyt and
• Darren L. Riley

Beilstein J. Org. Chem. 2018, 14, 1529–1536, doi:10.3762/bjoc.14.129

• Nicole C. Neyt Darren L. Riley Department of Chemistry, University of Pretoria, Pretoria 0002, South Africa 10.3762/bjoc.14.129 Abstract We recently reported a novel hybrid batch–flow synthesis of the antipsychotic drug clozapine in which the reduction of a nitroaryl group is described under flow

• reduction utilizing solid mixes of sodium borohydride, lithium chloride and celite [12], and the Ley group were able to demonstrate a green transfer hydrogenation of ketones under flow using catalytic lithium tert-butoxide in isopropanol [13]. We recently published a batch–flow hybrid synthesis of the

Three-component coupling of aryl iodides, allenes, and aldehydes catalyzed by a Co/Cr-hybrid catalyst

• Kimihiro Komeyama,
• Shunsuke Sakiyama,
• Kento Iwashita,
• Itaru Osaka and
• Ken Takaki

Beilstein J. Org. Chem. 2018, 14, 1413–1420, doi:10.3762/bjoc.14.118

• , whereas the chromium salt generates highly nucleophilic allylchromium intermediates from allylcobalt species, without the loss of stereochemical information, to allow the addition to aldehydes. Keywords: chromium; cobalt; diastereoselective; homoallyl alcohols; hybrid catalyst; three-component coupling

• three-component coupling method is herein reported for the direct synthesis of highly diastereoselective multi-substituted homoallyl alcohols employing a cobalt/chromium hybrid catalyst (Scheme 5). Results and Discussion Initially, suitable reaction conditions were investigated for the three-component

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

• donors in order to design novel bifunctional catalytic scaffolds [54][55]. Hybrid calixarene hosts bearing bis-squaramide moieties at the endo (or lower) and exo (or upper) rims and their recognition properties toward anionic guests have been already reported [56][57]. Therefore, it would be interesting

Are dispersion corrections accurate outside equilibrium? A case study on benzene

• Tim Gould,
• Erin R. Johnson and
• Sherif Abdulkader Tawfik

Beilstein J. Org. Chem. 2018, 14, 1181–1191, doi:10.3762/bjoc.14.99

• henceforth “on X” means that the correction is taken on top of the X (hybrid) density functional approximation, which we also denote as X-Y (e.g., PBE-D3-BJ); 2) atomic-dipole with density methods, which correct first-principles or empirical models of atomic dipoles (and sometimes multipoles) using

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

• as inhibitors of Werner and Bloom syndrome helicases and dual topoisomerase I/II inhibitors [37][38]. In order to improve DNA binding affinity and sequence specificity with reduced side effects, a series of synthetic hybrid molecules derived from distamycin and netropsin was synthesized and their

• fashion, they further reported a series of novel hybrids by tethering distamycin A with the antineoplastic agent uramustine via a flexible polymethylene chain of variable length (n = 1 to 6) in order to test their DNA binding affinity and cytotoxicity [57]. It has been observed that hybrid conjugates 8, 9

• by reducing aggregation and also helps to conduct a detailed thermodynamic study for the 8-ring HP polyamides for the very first time. Recently, Hartley et al. designed and synthesized a hybrid fluorescent HP polyamide conjugate 22 (Figure 6) by attaching the A·T recognizing fluorophore, p

Fluorocyclisation via I(I)/I(III) catalysis: a concise route to fluorinated oxazolines

• Felix Scheidt,
• Christian Thiehoff,
• Gülay Yilmaz,
• Stephanie Meyer,
• Constantin G. Daniliuc,
• Gerald Kehr and
• Ryan Gilmour

Beilstein J. Org. Chem. 2018, 14, 1021–1027, doi:10.3762/bjoc.14.88

• corresponding 1,2-difluoroethylene unit; a substructure that may be considered a chiral, hybrid bioisostere of the Et and CF3 groups (Figure 2, top) [36]. Since the success of this process is contingent on the efficient generation of p-TolIF2 in situ, the platform lends itself to related oxidative

The first Pd-catalyzed Buchwald–Hartwig aminations at C-2 or C-4 in the estrone series

• Ildikó Bacsa,
• Dávid Szemerédi,
• János Wölfling,
• Gyula Schneider,
• Lilla Fekete and
• Erzsébet Mernyák

Beilstein J. Org. Chem. 2018, 14, 998–1003, doi:10.3762/bjoc.14.85

• bearing a 3-OH group exhibited a substantial inhibitory effect against the 17β-HSD1 enzyme. Surprisingly, the enzyme inhibitory action did not depend on the hybrid state of carbon attached to C-2. From the pharmacological point of view it would be interesting to synthesize and investigate such 13α-estrone

Local energy decomposition analysis of hydrogen-bonded dimers within a domain-based pair natural orbital coupled cluster study

• Ahmet Altun,
• Frank Neese and
• Giovanni Bistoni

Beilstein J. Org. Chem. 2018, 14, 919–929, doi:10.3762/bjoc.14.79

• modified PBE0 hybrid functional in which the long-range tail contains 75% of LB94 exchange. The shift parameter applied for the bulk potential within this correction was calculated as the sum of the ionization potential and highest occupied molecular orbital (HOMO) energy of each fragment optimized in the

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

• case with DNA that is cleaved by an attack of an external nucleophile. Recent hybrid quantum mechanical/effective fragment potential (QM/EEP) calculations on the hydroxide-ion-catalyzed hydrolysis of diethyl phosphate monoanion, however, suggest that the acyclic phosphorane obtained still is an

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

• interface populated by catalyst particles. They deposited metallic Pd onto carbon nanotube–inorganic oxide hybrid nanoparticles and used them in emulsions for the hydrodeoxygenation of a phenolic compound and the hydrogenation and etherification of an aldehyde. The advantages of such a system include a high

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

• the roles of secondary carbohydrate binding sites, will provide new directions for the future development of inhibitors, for example, fucosylated polymers [75], or hybrid inhibitors that can target both the blood group and the GM1 binding pockets. While other emerging, and sophisticated strategies for

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

• siRNA–mRNA hybrid, disturbing the cleavage of mRNA by the RISC. Subsequently, Deiters used the same approach with photo 6-nitropiperonyloxymethyl (NPOM)-photocaged siRNAs synthesized from phosphoramidites of the caged uridine and guanosine ribonucleotides (Scheme 20B) [83]. As previously demonstrated

Synthetic and semi-synthetic approaches to unprotected N-glycan oxazolines

• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 416–429, doi:10.3762/bjoc.14.30

• transferases (namely a β(1–2)-GlcNAc transferase, a β(1–4)-galactosyltransferase, and an α(2–6)-sialyltransferase), and the corresponding hybrid N-glycan oxazoline used as a substrate for ENGases [110]. Conclusion N-Glycan oxazolines have found widespread use as activated donor substrates for ENGase enzymes, a

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

• the fabrication of highly emissive blue OLEDs. Devices fabricated with D6 furnished a maximum EQE of 19.5% and maintained the high EQE of 16% at 1000 cd/m2 with a satisfactory color purity of coordinates (0.16, 0.20). Recently, high-performance TADF based hybrid WOLEDs employing D6 as the blue emitter

• were successfully fabricated [44]. Interestingly, WOLEDs showed excellent device characteristics with an EQE of 23.0%, a current and power efficiency of 51.0 cd/A and 51.7 lm/W, respectively. These performances are among the highest values reported to date for hybrid WOLEDs using a TADF material as the

Fluorogenic PNA probes

• Tirayut Vilaivan

Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17

• binding domain and the stem part consisted of a chimeric PNA–DNA hybrid linked together by a disulfide bond (Figure 4). The chimeric beacon was immobilized to a microtiter plate via a biotin tag and was employed for the detection of PCR amplicons of rDNA from Entamoeba histolytica [41]. The use of PNA

• ]. Interestingly, switching in the opposite direction, when the excimer signal is enhanced upon hybrid formation, was observed in triplex forming double-pyrene-labeled aegPNA probes [69]. For FRET-based PNA beacons, these have so far been investigated in the context of FIT PNA probes (vide infra), which will be

• detection of 16S RNA from a single cell of Escherichia coli [79]. In addition to the detection of DNA and RNA targets, hybrid PNA-peptide beacons were designed for the detection of non-DNA targets, such as proteins (Figure 10A). According to this design, which was simultaneously proposed in 2007 by Seitz

Synthesis and spectroscopic properties of β-meso directly linked porphyrin–corrole hybrid compounds

• Baris Temelli and
• Hilal Kalkan

Beilstein J. Org. Chem. 2018, 14, 187–193, doi:10.3762/bjoc.14.13

• -5,10,15,20-tetraphenylporphyrins with meso-substituted dipyrromethanes. Hybrid compounds have been characterized by 1H NMR, 13C NMR, 2D NMR, UV–vis absorption and fluorescence spectroscopy. Keywords: corrole; hybrid compounds; indium(III) chloride; porphyrin; porphyrinoids; Introduction Porphyrins and

• conjugates, systematic studies on directly linked porphyrin–corrole hybrid structures are limited and there is no report on β-porphyrin, meso-corrole linked hybrids of these conjugates. Zheng et al. synthesized meso–meso directly linked porphyrin–corrole dyads by the condensation reaction of meso-formylated

• -porphyrin, β-corrole-linked hybrid structure described a Suzuki–Miyaura cross-coupling reaction between a β-borylated corrole and meso-bromoporphyrins (Scheme 1D) [37]. Recently, we have successfully synthesized meso–meso and β-meso-linked imine-bridged porphyrin–corrole conjugates and investigated

Polarization spectroscopy methods in the determination of interactions of small molecules with nucleic acids – tutorial

• Tamara Šmidlehner,
• Ivo Piantanida and
• Gennaro Pescitelli

Beilstein J. Org. Chem. 2018, 14, 84–105, doi:10.3762/bjoc.14.5

Aminosugar-based immunomodulator lipid A: synthetic approaches

• Alla Zamyatina

Beilstein J. Org. Chem. 2018, 14, 25–53, doi:10.3762/bjoc.14.3

• owing to enhanced amphiphilicity of the hybrid molecule inflicted by the hydrophobic character of the fluorescent label and the formation of aggregates which resulted in self-quenching. To circumvent these problems, a longer hydrophilic linker and a less hydrophobic fluorescent group were required. An

Nucleophilic dearomatization of 4-aza-6-nitrobenzofuroxan by CH acids in the synthesis of pharmacology-oriented compounds

• Alexey M. Starosotnikov,
• Dmitry V. Shkaev,
• Maxim A. Bastrakov,
• Ivan V. Fedyanin,
• Svyatoslav A. Shevelev and
• Igor L. Dalinger

Beilstein J. Org. Chem. 2017, 13, 2854–2861, doi:10.3762/bjoc.13.277

• heteroaromatics combining several pharmacophoric moieties in the same molecule, interesting from the standpoint of design of novel pharmaceuticals. The work continues our ongoing project on the synthesis of complex hybrid molecules – furoxan-containing potential NO donors [19][20][21][22][23][24]. Results and

Pyrene–nucleobase conjugates: synthesis, oligonucleotide binding and confocal bioimaging studies

• Artur Jabłoński,
• Yannic Fritz,
• Hans-Achim Wagenknecht,
• Rafał Czerwieniec,
• Tytus Bernaś,
• Damian Trzybiński,
• Krzysztof Woźniak and
• Konrad Kowalski

Beilstein J. Org. Chem. 2017, 13, 2521–2534, doi:10.3762/bjoc.13.249

• using the density functional theory (DFT) with the hybrid gradient corrected correlation functional B3LYP [38] and Gaussian-type basis functions 6-311G(d,p) [39]. TD-DFT calculations were performed in the optimized ground state geometry using the same B3LYP functional and basis sets. Five lowest singlet

Solvent-free copper-catalyzed click chemistry for the synthesis of N-heterocyclic hybrids based on quinoline and 1,2,3-triazole

• Martina Tireli,
• Silvija Maračić,
• Stipe Lukin,
• Marina Juribašić Kulcsár,
• Dijana Žilić,
• Mario Cetina,
• Ivan Halasz,
• Silvana Raić-Malić and
• Krunoslav Užarević

Beilstein J. Org. Chem. 2017, 13, 2352–2363, doi:10.3762/bjoc.13.232

• , Figures S11–S14). Computational details. Calculations were carried out using the B3LYP hybrid functional combined with an empirical Grimme’s D3 dispersion correction [55] (B3LYP-D3) implemented in Gaussian 09 [56]. The standard 6-311+G(2d,p) basis set with the ultrafine method was used for C, H, N, F, Cl

Synthesis and application of trifluoroethoxy-substituted phthalocyanines and subphthalocyanines

• Satoru Mori and
• Norio Shibata

Beilstein J. Org. Chem. 2017, 13, 2273–2296, doi:10.3762/bjoc.13.224

• semiconductors [102]. For example, a hybrid compound consisting of phthalocyanine and fullerene 20a causes the transfer of energy from the phthalocyanine unit to the fullerene unit when irradiated by light (Figure 6) [103][104]. However, such energy transfer does not occur in the hybrid of TFEO-ZnPc and

• was obtained at a rate of 68%. This is because the stability of subphthalocyanine and the reactivity of the substitution reaction at the axial position are improved by the introduction of a trifluoroethoxy group. Using this high reactivity of axial substitution, hybrid dyes in which the axial position

• of TFEO-subPc is substituted with fullerene 27 or phthalocyanine 28 intended to construct energy transfer systems have been synthesized (Figure 7). In the previous section, it was explained that the hybrid dye of TFEO-ZnPc and fullerene does not cause energy transfer between units, but in this case

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• bone targeting, for the design of supramolecular or hybrid materials, for the functionalization of surfaces, for analytical purposes, for medical imaging or as phosphoantigen. These applications are covering a large panel of research fields including chemistry, biology and physics thus making the

• phosphorus-containing functional groups [2], on specific applications (hybrid materials [3], surface modification [4], oil industry [5]) or dedicated to a family of compounds (e.g., aminophosphonic acids [6], organometallic phosphonic acids [7]). However, no recent review was focused on the different methods

• chemosensor for trinitrotoluene (TNT) [63]. The third important feature of phosphonic acid arises from its coordination properties. Indeed, the three oxygen atoms can be engaged in coordination or iono-covalent bonds. These coordination properties were used to design molecular hybrid materials [64] also

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• attachments that could provide more flexibility in the synthesis of longer oligosaccharides [62][65]. Some representative examples of this general concept include benzyl–silicon tether [72], which is a hybrid approach to xylylene and a regular silicon [59] type of tethering. Another example of a non

• -symmetrical tethering strategy is benzyl–benzoyl hybrid tethering [72] that elaborated on xylylene and phthaloyl tethering approaches discussed above. Thus, this strategy was used in the synthesis of a trisaccharide through reiterative template-assisted synthesis (Scheme 11). Compound 41, wherein the donor

• and acceptor counterparts were subjected to tethering via this rigid hybrid linker, was subjected to the NIS/TfOH-promoted glycosylation. The tether in the resulting disaccharide 42 could then be selectively opened with NaOMe. This leads to liberating only one hydroxy group (at C-3”) that could be