Diels–Alder reaction of β-fluoro-β-nitrostyrenes with cyclic dienes

• Savva A. Ponomarev,
• Roman V. Larkovich,
• Alexander S. Aldoshin,
• Andrey A. Tabolin,
• Sema L. Ioffe,
• Jonathan Groß,
• Till Opatz and
• Valentine G. Nenajdenko

Beilstein J. Org. Chem. 2021, 17, 283–292, doi:10.3762/bjoc.17.27

• File 206: Copies of spectra, experimental section, and computational details of DFT calculations. Acknowledgements The authors acknowledge the partial support in measuring of NMR spectra from the M. V. Lomonosov Moscow State University Program of Development. We thank Jan Brauer and Paul Eckhardt for

Exploring the possibility of using fluorine-involved non-conjugated electron-withdrawing groups for thermally activated delayed fluorescence emitters by TD-DFT calculation

• Dongyang Chen and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 210–223, doi:10.3762/bjoc.17.21

• states between S1 and T1, thus likely leading to a very efficient reverse intersystem crossing in these compounds. Keywords: DFT calculation; pentafluorosulfanyl; spin-orbit coupling; TADF; trifluoromethoxy; trifluoromethylthio; Introduction Organic thermally activated delayed fluorescence (TADF

• states, followed by rISC [22]. This situation typically occurs when there are multiple donors about a single acceptor as exists in the molecules 5CzBN and 5CzTRZ. For 5CzBN, time-dependent density functional theory (TD-DFT) calculation revealed the existence of three intermediate triplet states [22]. The

• presence of these states helped to explain the short τd of 3.7 μs and the high EQEmax of 17% and good device stability with a T50 of 176 hours for the OLED [CIE coordinate (0.22, 0.40)] [23]. In an analogous manner, TD-DFT calculations predicted 5CzTRZ to possess a small ΔEST (0.02 eV) as well as a small

Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams

• Michał M. Więcław and
• Bartłomiej Furman

Beilstein J. Org. Chem. 2021, 17, 115–123, doi:10.3762/bjoc.17.12

• azide addition to nitriles [45]. It is important to note that the computational investigation of this reaction mechanism was not a primary goal of this work. That said, we consider this simple, crude DFT research to support our model of the transformation described herein. Conclusion During the course

• requires protic conditions, in opposition to what is generally agreed upon for these type of reactions. An alternative reaction mechanism is proposed and provisionally confirmed with DFT calculations. Moreover, selected α-tetrazolyl-iminosugars were subjected to further transformations, yielding new

Pentannulation of N-heterocycles by a tandem gold-catalyzed [3,3]-rearrangement/Nazarov reaction of propargyl ester derivatives: a computational study on the crucial role of the nitrogen atom

• Giovanna Zanella,
• Martina Petrović,
• Dina Scarpi,
• Ernesto G. Occhiato and
• Enrique Gómez-Bengoa

Beilstein J. Org. Chem. 2020, 16, 3059–3068, doi:10.3762/bjoc.16.255

• substrates. Keywords: DFT calculations; gold catalysis; Nazarov reaction; N-heterocycles; Introduction In the development of new and effective catalysts, step economy is surely one of the major goals. A reduction of the number of steps in the synthesis of complex compounds can be attained by cascade

• sluggish reactivity of the 3-substituted substrates, in comparison to the 2-substituted analogues that we have previously described. Tandem acetate rearrangement/Nazarov cyclization of different substrates. DFT-computed energy profile of the tandem Au(I)-catalyzed [3,3]-rearrangement/Nazarov reaction of 3

• -substituted piperidine derivatives. DFT-computed energy profile of the tandem Au(I)-catalyzed [3,3]-rearrangement/Nazarov reaction of 2-substituted piperidine derivatives. Computed comparison of the NBO charges of 2- and 3-substituted substrates. Single-step transformation of IV to IX. Triflate-promoted

Naphthalonitriles featuring efficient emission in solution and in the solid state

• Sidharth Thulaseedharan Nair Sailaja,
• Iván Maisuls,
• Jutta Kösters,
• Alexander Hepp,
• Andreas Faust,
• Jens Voskuhl and
• Cristian A. Strassert

Beilstein J. Org. Chem. 2020, 16, 2960–2970, doi:10.3762/bjoc.16.246

• contributing to the emissive singlet state cannot be entirely ruled out; besides the obvious lack of solvent stabilization in frozen matrices, a TICT suppression at 77 K can also account for the blue-shifted emission in the frozen glassy matrix. However, further transient-absorption experiments and TD-DFT

UV resonance Raman spectroscopy of the supramolecular ligand guanidiniocarbonyl indole (GCI) with 244 nm laser excitation

• Tim Holtum,
• Vikas Kumar,
• Daniel Sebena,
• Jens Voskuhl and
• Sebastian Schlücker

Beilstein J. Org. Chem. 2020, 16, 2911–2919, doi:10.3762/bjoc.16.240

• the results from density functional theory (DFT) calculations. Keywords: GCI; GCP; guanidiniocarbonyl indole; guanidiniocarbonyl pyrrole; UVRR; Raman spectroscopy; resonance Raman; Introduction Supramolecular ligands are capable to selectively bind to peptides and proteins via reversible non

• –1800 cm−1. Peaks appearing within the 900–1100 cm−1 region cover various pyrrole ring deformation modes while the peak at 1400 cm−1 belongs to a symmetrical half-ring vibration of pyrrole [13]. Based on the results from DFT calculations [13], the peaks around 1470 cm−1 are assigned to N–H bending and C

• the results from density functional theory (DFT) calculations. The assignment of the peaks detectable in the experimental UVRR spectrum is mainly based on the experimental wavenumber position (peak position). Only normal modes with non-vanishing Raman activities were considered. One cannot expect an

Fluorine effect in nucleophilic fluorination at C4 of 1,6-anhydro-2,3-dideoxy-2,3-difluoro-β-D-hexopyranose

• Danny Lainé,
• Vincent Denavit,
• Olivier Lessard,
• Laurie Carrier,
• Charles-Émile Fecteau,
• Paul A. Johnson and
• Denis Giguère

Beilstein J. Org. Chem. 2020, 16, 2880–2887, doi:10.3762/bjoc.16.237

• density functional theory (DFT) calculations). Finally, we wish to report the preparation of novel multi-vicinal fluorinated alditol analogues using a simple reduction protocol. Results and Discussion We initially supposed that DAST, a commonly used reagent to install fluorine atoms on the carbohydrate

• , DFT calculations were performed with Gaussian 09, revision E.01 [44] to evaluate the hypothesis for the formation of oxiranium ion A. Calculations were performed with the CAM-B3LYP functional [45][46][47] using Grimme’s D3 dispersion correction [48] and the 6-31+G(d,p) basis set. The results of our

Ring-closing metathesis of prochiral oxaenediynes to racemic 4-alkenyl-2-alkynyl-3,6-dihydro-2H-pyrans

• Viola Kolaříková,
• Markéta Rybáčková,
• Martin Svoboda and
• Jaroslav Kvíčala

Beilstein J. Org. Chem. 2020, 16, 2757–2768, doi:10.3762/bjoc.16.226

• -2,7-diyne reacted chemo- and stereoselectively in a Diels–Alder reaction with N-phenylmaleimide affording the tricyclic products as a mixture of two separable diastereoisomers, the configuration of which was estimated by DFT computations. The reported enediyne metathesis paves the way to the

• ]. The reaction at rt in dichloromethane gave the target product 14 in a moderate 45% isolated yield as a mixture of two diastereoisomers (Scheme 14). Pure diastereoisomers were obtained by column chromatography in 24% and 17% yield, respectively. DFT study of the Diels–Alder reaction of compounds 12b

• obtained two diastereoisomers, we decided to perform a short DFT study of the Diels–Alder reaction between dihydropyran 12b and maleimide 13. We started the study with the optimization of the starting compound. While the optimization of the rigid maleimide 13 was straightforward, 18 conformations had to be

Synthesis of purines and adenines containing the hexafluoroisopropyl group

• Viacheslav Petrov,
• Rebecca J. Dooley,
• Alexander A. Marchione,
• Elizabeth L. Diaz,
• Brittany S. Clem and
• William Marshall

Beilstein J. Org. Chem. 2020, 16, 2739–2748, doi:10.3762/bjoc.16.224

• 3a at 253 K. Right: Eyring plot of the interconversion of the rotamers of 3a. DFT-optimized structures of the two rotamers of 3a. Left: Lower-energy rotamer. Right: Higher-energy rotamer. Reaction of purine (2) with tetrakis(trifluoromethyl)-1,3-dithietane (1). Reaction of 4-azabenzimidazole (3) with

Vicinal difluorination as a C=C surrogate: an analog of piperine with enhanced solubility, photostability, and acetylcholinesterase inhibitory activity

• Yuvixza Lizarme-Salas,
• Alexandra Daryl Ariawan,
• Ranjala Ratnayake,
• Hendrik Luesch,
• Angela Finch and
• Luke Hunter

Beilstein J. Org. Chem. 2020, 16, 2663–2670, doi:10.3762/bjoc.16.216

• . This was achieved by performing a DFT study in the Gaussian software, using the M06-2X level of theory with the 6-311+G(d,p) basis set, parameters similar to those employed by Linclau and co-workers for their studies of vicinal difluoro systems [22]. A set of starting structures of 2 was generated by

• physicochemical properties of compound 2 were found to be superior to piperine (1) itself in two key respects, namely photostability and aqueous solubility. The conformational analysis of 2 by DFT and NMR spectroscopy revealed that the lowest-energy conformations 2a–c are imperfect mimics of 1 but that a somewhat

• for this work; the crystal structure is shown [14]. In this work, a hypothetical analog 2 was designed to mimic parent compound 1. The predicted low-energy rotamers of 2 about the F–C–C–F and F–C–C=O bonds are shown; rotamers I and IV give the best mimicry of 1. Conformational analysis of 2 by DFT and

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

• defined as the ratio of the micropore volume to the total pore volume. The relative errors were estimated to be the following: SBET, 5%; pore volume (pv, DFT), 5%; pore size (ps, DFT), 20%. Isotherms were measured on a Quantachrome® ASiQwin™ instrument at 0 and 21 °C. The temperature was held constant

Synthesis of 4-substituted azopyridine-functionalized Ni(II)-porphyrins as molecular spin switches

• Jannis Ludwig,
• Tobias Moje,
• Fynn Röhricht and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2589–2597, doi:10.3762/bjoc.16.210

• is always in a high paramagnetic state (>80%) and showed only minor switching efficiency after irradiation (4%). This is attributed to intramolecular coordination of the trans state (Supporting Information File 1, Figure S17). Application of density functional theory (DFT) at the B3LYP/def2TZVP//PBE

Water-soluble host–guest complexes between fullerenes and a sugar-functionalized tribenzotriquinacene assembling to microspheres

• Si-Yuan Liu,
• Xin-Rui Wang,
• Man-Ping Li,
• Wen-Rong Xu and
• Dietmar Kuck

Beilstein J. Org. Chem. 2020, 16, 2551–2561, doi:10.3762/bjoc.16.207

• Ka = (2.20 ± 0.16) × 105 M−1, respectively. The binding affinity between TBTQ-(OG)6 and C60 was further verified by Raman spectroscopy. The geometry of the complex of TBTQ-(OG)6 with C60 deduced from DFT calculations indicates that the driving force of the complexation is mainly due to the

• diffraction. Therefore, the optimized geometry of the 1:1 complex of TBTQ-(OG)6 C60 in water was simulated by density functional theory (DFT) calculations at the B3LYP/6-31G(d) level of theory, which was completed with the aid of Molclus, MOPAC, and ORCA 4.1.0 programs [54][55][56]. As shown in Figure 6, C60

• were dried on a slide glass. C60 was tested in powder form on a slide glass. Molecular model of the complex TBTQ-(OG)6 C60 in water, as generated by DFT calculations. (a) Side-view; (b) top-view; (c) hydrophobic surface diagram. In part, H atoms were omitted for clarity (yellow: C, red: O, blue: N

Conformational preferences of fluorine-containing agrochemicals and their implications for lipophilicity prediction

• Daniela Rodrigues Silva,
• Joyce K. Daré and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2020, 16, 2469–2476, doi:10.3762/bjoc.16.200

• high degree of freedom in the chemical structure of penoxsulam (I), the conformational analysis started with a Monte Carlo conformational search at the ωB97X-D/6-31G(d,p) [16][17] level of the density functional theory (DFT). The global energy minimum conformation was then re-optimized in a higher

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

Styryl-based new organic chromophores bearing free amino and azomethine groups: synthesis, photophysical, NLO, and thermal properties

• Anka Utama Putra,
• Deniz Çakmaz,
• Nurgül Seferoğlu,
• Alberto Barsella and
• Zeynel Seferoğlu

Beilstein J. Org. Chem. 2020, 16, 2282–2296, doi:10.3762/bjoc.16.189

• dyes bearing the julolidine donor as 1430 × 10−48 esu (for free amino derivative) and 1950 × 10−48 esu (for Schiff base derivative), respectively. The structural and electronic properties of the dyes as well as their NLO properties were further studied using DFT calculations. The thermal stabilities of

• all dyes were evaluated by thermogravimetric analysis (TGA). The TGA data showed that all dyes were thermally stable up to 250 °C. Keywords: DFT calculations; NLO; pH sensitive dyes; Schiff base; solvent effect; styryl dyes; Introduction Push-pull organic molecules are a class of organic dyes

• series of new styryl-based organic chromophores containing a free amino group and the corresponding Schiff base derivatives. The photophysical, pH sensitivity, NLO properties, and thermal stabilities of all synthesized dyes were investigated. Density Functional Theory (DFT) calculations were also

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• thermoelectric properties in addition to the onigiri-type core-shell assemblies have been reported for sumanene and its derivatives. More interestingly, its application in the absorption of small molecules such as NH3, CO2, CO, and H2 using density functional theory (DFT) calculations has also been revealed [25

• /mol) transformation of 12 (syn) to 17, calculated by density functional theory (DFT) calculations. On the other hand, in 2008, Higashibayashi et al. reported the synthesis of first chiral C3-symmetric trimethylsumanene 28 starting from enantiopure norbornadiene (10) by employing a rational synthetic

• (DFT) calculations. As we are aware that if the carbene formed is a singlet then a C–H bond inserted product is predominating whereas if the dimer is the major product along with the minor C–H bond inserted product then the triplet carbene is generated. During their study, they obtained the C–H

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• TA spectra. The direct reaction between AQN and the substrate was not observed by TAS. The authors’ DFT calculations revealed reaction pathways that were thermodynamically and kinetically plausible. Initially, AQN and Selectfluor® (S0 in Scheme 16) form a van der Waals complex RC1, which is markedly

Lipophilicity trends upon fluorination of isopropyl, cyclopropyl and 3-oxetanyl groups

• Benjamin Jeffries,
• Zhong Wang,
• Robert I. Troup,
• Anaïs Goupille,
• Jean-Yves Le Questel,
• Charlene Fallan,
• James S. Scott,
• Elisabetta Chiarparin,
• Jérôme Graton and
• Bruno Linclau

Beilstein J. Org. Chem. 2020, 16, 2141–2150, doi:10.3762/bjoc.16.182

• even for a set of relatively simple compounds, fragment-based clogP calculations are not guaranteed to give reliable lipophilicity data. Next, theoretical lipophilicities were obtained using DFT calculations, based on the notion that the partition coefficient of a given solute between two phases

• provide any useful approximation in terms of rank order or absolute magnitude of effect. For series D, E, G, the DFT-logP values cluster together with minimal lipophilicity differences, and within mean absolute error limits (estimated to be around 0.8 logP units), making detailed considerations

• meaningless. This was a surprise, as series D and E are relatively rigid, which simplifies conformational analysis. The remarkably similar DFT-logP values suggest that the influence of the fluorination is underrepresented in the calculations. The following observations are noteworthy. The trifluorinated D5

Muyocopronones A and B: azaphilones from the endophytic fungus Muyocopron laterale

• Ken-ichi Nakashima,
• Junko Tomida,
• Tomoe Tsuboi,
• Yoshiaki Kawamura and
• Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 2100–2107, doi:10.3762/bjoc.16.177

• ) [25]. After conformational analysis, geometry optimization was performed for two possible stereoisomers with the (7S,10R,11R)- and (7S,10S,11S)-configurations using density functional theory (DFT) at the CAM-B3LYP/6-311+G(d,p) level of theory. In addition, the ECD spectra of the DFT-optimized

• conformers were calculated using time-dependent DFT (TDDFT) at the B3LYP/6-311+G(d,p) level of theory. The negative Cotton effect observed at 236 nm in the measured spectrum was in good agreement with that in the calculated ECD spectrum of the (7S,10R,11R)-stereoisomer (Figure 4A). Thus, the absolute

• –7.62 (m, 10H, phenyl groups of MTPAs). Computational methods Calculation of the ECD spectra were performed using CONFLEX 8, Gaussian 16, and SpecDis software as described previously [13][14]. Geometry optimizations were performed using DFT at the CAM-B3LYP/6-311+G(d,p) level of theory, while TDDFT

Naphthalene diimide–amino acid conjugates as novel fluorimetric and CD probes for differentiation between ds-DNA and ds-RNA

• Annike Weißenstein,
• Myroslav O. Vysotsky,
• Ivo Piantanida and
• Frank Würthner

Beilstein J. Org. Chem. 2020, 16, 2032–2045, doi:10.3762/bjoc.16.170

• substituents in the imide positions and on the nitrogen on the core are known to have a negligible effect on the chromophore, since both the HOMO and the LUMO have a node at these positions [33]. Geometry optimization by DFT method (at the B3LYP/6-31+G** level of theory) confirmed a planar and rigid NDI

• molecular ground-state electrical dipole (µ = 7.04 D), which is an evidence for an intramolecular charge transfer (CT) character of the chromophore [34]. The predicted UV–vis spectra by TD-DFT are in excellent agreement with the experimental one (Figure 3, Table 1, the vibrational coupling is neglected

• ). b) The molecular ground state dipole moment is indicated by the black arrow. The transition dipole moments calculated by TD-DFT (at the B3LYP/6-31+G** level of theory) for the lowest transitions in the visible range of the spectrum (indicated in the spectra by the red and blue arrows) are shown

A complementary approach to conjugated N-acyliminium formation through photoredox-catalyzed intermolecular radical addition to allenamides and allencarbamates

• Olusesan K. Koleoso,
• Matthew Turner,
• Felix Plasser and
• Marc C. Kimber

Beilstein J. Org. Chem. 2020, 16, 1983–1990, doi:10.3762/bjoc.16.165

• findings on the performance of allenamides. Specifically, the electron-withdrawing group on the allenamide and the nucleophile is examined. We provide evidence for the formation of the N-acyliminium intermediate through direct sample loop and flow injection analysis by HRESIMS, and DFT analysis of the N

• ]+); this peak persisted at 15, 30, 60 and 120 min time intervals, respectively. Upon the oxidation of 41 two plausible iminium stereoisomers can be formed, Z-42 and E-42, respectively, with each of these iminium stereoisomers existing in two further conformers designated E-42’ and Z-42’. DFT calculations

Synthesis, docking study and biological evaluation of ᴅ-fructofuranosyl and ᴅ-tagatofuranosyl sulfones as potential inhibitors of the mycobacterial galactan synthesis targeting the galactofuranosyltransferase GlfT2

• Marek Baráth,
• Jana Jakubčinová,
• Zuzana Konyariková,
• Stanislav Kozmon,
• Katarína Mikušová and
• Maroš Bella

Beilstein J. Org. Chem. 2020, 16, 1853–1862, doi:10.3762/bjoc.16.152

• mechanism studies using computational chemistry methods. The probable reaction mechanisms were studied by hybrid DFT QM/MM molecular dynamics simulations [11] where the possible transition state (TS) structures were localized. The observation of the possible TS structure opens the opportunities for the in

One-pot synthesis of oxazolidinones and five-membered cyclic carbonates from epoxides and chlorosulfonyl isocyanate: theoretical evidence for an asynchronous concerted pathway

• Esra Demir,
• Ozlem Sari,
• Yasin Çetinkaya,
• Ufuk Atmaca,
• Safiye Sağ Erdem and
• Murat Çelik

Beilstein J. Org. Chem. 2020, 16, 1805–1819, doi:10.3762/bjoc.16.148

• advantageous: being a one-pot reaction with metal-free reagent, having shorter reaction times, good yields and a very simple purification method. Moreover, using the density functional theory (DFT) method at the M06-2X/6-31+G(d,p) level of theory the mechanism of the cycloaddition reactions has been elucidated

Pauson–Khand reaction of fluorinated compounds

• Jorge Escorihuela,
• Daniel M. Sedgwick,
• Alberto Llobat,
• Mercedes Medio-Simón,
• Pablo Barrio and
• Santos Fustero

Beilstein J. Org. Chem. 2020, 16, 1662–1682, doi:10.3762/bjoc.16.138

• substituents such as dimethylaminium, trifluoromethyl, and acetyl favored the β-regioisomer (71B). The 4-fluorine substituted diarylalkynes had a very weak EWG effect yielding an equimolar mixture of both regioisomers. The experimental results were confirmed by a DFT study of the NBO charges of the α-alkyne