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

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

• calculations are needed in order to confirm this hypothesis, which is object of ongoing studies. Nonetheless, due to the fact that a vibrational progression is not observed at 77 K, TICT would only account to a minor extent. All the emission spectra and time-resolved photoluminescence decay curves are

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

• , 372.1570; found, 372.1571. Computational details DFT calculations were performed using the Gaussian 16 program suite [43]. For visualizations, the GaussView 6 interface program was used [44]. Due to economy, the pure M06L functional [45], def2-SV(P) basis set [46], and resolution of identity approximation

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

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

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

• ]+); 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

Rearrangement of o-(pivaloylaminomethyl)benzaldehydes: an experimental and computational study

• Csilla Hargitai,
• Györgyi Koványi-Lax,
• Tamás Nagy,
• Péter Ábrányi-Balogh,
• András Dancsó,
• Gábor Tóth,
• Judit Halász,
• Angéla Pandur,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2020, 16, 1636–1648, doi:10.3762/bjoc.16.136

• )benzaldehydes under acidic conditions resulted in the formation of the regioisomeric aldehydes and/or dimer-like products. Detailed NMR studies and single-crystal X-ray measurements supported the structure elucidation of the compounds. DFT calculations were also carried out to clarify the reaction mechanism

• , and to explain the observed product distributions and structural variances in the dimer-like products. Studies on the transformation of unsubstituted o-(pivaloylaminomethyl)benzaldehyde under similar conditions were presented as well. Keywords: DFT calculations; NMR; reaction mechanism; rearrangement

• reaction described in Scheme 1 to further o-(pivaloylaminomethyl)benzaldehydes and to support the results by density functional theory (DFT) calculations, single-crystal X-ray measurements and comprehensive NMR studies. Results and Discussion Acid-catalyzed transformations of compounds 1a–d First we kept

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• measurements, TRPL spectroscopy, and density functional theory (DFT) calculations. They found that the HER efficiency correlated to the excited state lifetime and exciton binding energy. The FSO-BP and FSO-FSz hindered the charge transfer and mobility due to the phenyl–phenyl dihedral angle or sharp bends in

In silico rationalisation of selectivity and reactivity in Pd-catalysed C–H activation reactions

• Liwei Cao,
• Mikhail Kabeshov,
• Steven V. Ley and
• Alexei A. Lapkin

Beilstein J. Org. Chem. 2020, 16, 1465–1475, doi:10.3762/bjoc.16.122

• computational data, a threshold to distinguish between two possible reaction mechanisms was established. Computational Methods The NWChem, an open source software package, was used for the DFT calculations. It is easily scalable and designed to solve large scientific computational problems efficiently employing

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

• Shigeyuki Yamada,
• Takuya Higashida,
• Yizhou Wang,
• Masato Morita,
• Takuya Hosokai,
• Kaveendra Maduwantha,
• Kaveenga Rasika Koswattage and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102

• –405 nm (ε: 180–260 M−1·cm−1). To gain more information about the slight difference between the absorption behaviors of the benzil and bisbenzil derivatives, DFT and time-dependent DFT (TD-DFT) calculations at the CAM-B3LYP/6-31+G(d) level of theory were performed for fluorinated benzil 2a and

• procedures for the synthesis and characterization of fluorinated benzils 2a and 2b, fluorinated bisbenzils 3a and 3b, and nonfluorinated bisbenzil 3c. 1H, 13C, and 19F NMR spectra of 2a, 2b, and 3a–c. Cartesian coordinates of the optimized geometries of 1a, 1c, 2a, and 3a obtained from DFT calculations

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• [15]. Theoretical calculations and electrochemical properties DFT calculations were employed to gain insight into the structure–property relationships of the quinazoline-based derivatives 1–3. The compounds have phenyl spacers between the donor and acceptor units (Figure 2). Therefore, the dihedral

• energy values at the corresponding excited-state geometry. The time-dependent DFT (TD-DFT) calculations were carried out with the Gaussian 16 software package and molecular orbitals were visualized by using Gaussview. Photoelectron emission spectroscopy measurement was performed according to the

Aryl-substituted acridanes as hosts for TADF-based OLEDs

• Naveen Masimukku,
• Dalius Gudeika,
• Oleksandr Bezvikonnyi,
• Ihor Syvorotka,
• Rasa Keruckiene,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 989–1000, doi:10.3762/bjoc.16.88

• . Theoretical calculations The optimized structures of 3–6 were obtained by density functional theory (DFT) calculations at the B3LYP/6-31G(d,p) level of theory (Figure 1). The dihedral angles between the acridanyl and phenyl moieties in compound 3 (37.0 and 36.3°) are comparable with the dihedral angles

• , 29.3, 11.7; MS (APCI+, 20 V) m/z: 426 ([M + H]+); anal. calcd for C29H25F2N: C, 81.86; H, 5.92; F, 8.93; N, 3.29; found: C, 81.91; H, 5.99; N, 3.31%. Theoretically calculated HOMO and LUMO levels distributions and optimized geometries of 3–6 DFT calculations were performed at the B3LYP/6-31G(d,p) level

Synthesis and properties of tetrathiafulvalenes bearing 6-aryl-1,4-dithiafulvenes

• Aya Yoshimura,
• Hitoshi Kimura,
• Kohei Kagawa,
• Mayuka Yoshioka,
• Toshiki Itou,
• Dhananjayan Vasu,
• Takashi Shirahata,
• Hideki Yorimitsu and
• Yohji Misaki

Beilstein J. Org. Chem. 2020, 16, 974–981, doi:10.3762/bjoc.16.86

• ; one was the palladium-catalyzed C–H arylation of TTF with bromide 12 (Scheme 2a) and the other was the Vilsmeier–Haack reaction of 1a, followed by triethyl phosphite-mediated cross coupling with 11 (Scheme 2b). Theoretical calculations The DFT calculations of compounds 1a, 3a, and 4 have been carried

• is participating in this redox process is surrounded by extended aromatic rings bearing 1,3-dithiol rings. Conclusion We have synthesized novel multistage TTF derivatives 1–4 bearing 6-aryl-1,4-dithiafulvene moieties by palladium-catalyzed direct C–H arylation. The DFT calculations revealed the

Cation-induced ring-opening and oxidation reaction of photoreluctant spirooxazine–quinolizinium conjugates

• Phil M. Pithan,
• Sören Steup and
• Heiko Ihmels

Beilstein J. Org. Chem. 2020, 16, 904–916, doi:10.3762/bjoc.16.82

• discussed in the literature whether metal cations are coordinated in a monodentate fashion to the phenolate oxygen atom or rather in a bidentate fashion both to the phenolate oxygen and the imine nitrogen atoms of the open merocyanine form [25][28]. Furthermore, density functional theory (DFT) calculations

Bipyrrole boomerangs via Pd-mediated tandem cyclization–oxygenation. Controlling reaction selectivity and electronic properties

• Liliia Moshniaha,
• Marika Żyła-Karwowska,
• Joanna Cybińska,
• Piotr J. Chmielewski,
• Ludovic Favereau and
• Marcin Stępień

Beilstein J. Org. Chem. 2020, 16, 895–903, doi:10.3762/bjoc.16.81

• using NMR spectroscopy and DFT calculations [33]. In particular, the unprecedented double α-oxygenation of bipyrroles was shown to occur through stepwise acetoxylation, which we found to compete with α–α oligomerization. These new bipyrrole boomerangs exhibited enhanced fluorescence with Φfl values of

• DFT calculations (Figure 1 and Supporting Information File 1). The length of the linker (n) in cNDAnX and cNMInX controls the in- and out-of-plane geometry of the chromophore. The observed changes can be expressed in terms of two parameters: α, the angle between the monopyrrole axis and the N–N vector

• measurements, without any significant loss of the unpolarized emission intensity. This behavior, which precluded a quantitative analysis of the CPL properties, may be attributed to a photoinduced racemization process. The differences in configurational stability of boomerangs are reproduced by DFT calculations

One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation

• Ji Ma,
• Yubin Fu,
• Junzhi Liu and
• Xinliang Feng

Beilstein J. Org. Chem. 2020, 16, 791–797, doi:10.3762/bjoc.16.72

• -membered rings on the peropyrene core, the electronic structures and the frontier orbitals of the peropyrene derivative 6 without pentagons and of compound 1 are compared by DFT calculations at the B3LYP/6-311++G(d,p) level. As shown in Figure 4, the LUMO and HOMO of 6 are both delocalized over the

• -diphenylpyrene is the key step. The single crystal X-ray diffraction analysis revealed a twisted structure of 1 due to the steric hindrance at the bay positions. From the bond length analysis and DFT calculations, CP-PAH 1 consists of the aromatic peropyrene core with two slightly antiaromatic peri-fused five

Recent advances in Cu-catalyzed C(sp³)–Si and C(sp³)–B bond formation

• Balaram S. Takale,
• Ruchita R. Thakore,
• Elham Etemadi-Davan and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

• an appropriate electrophile led to C–C bond formation, ultimately delivering chiral tertiary alcohols. Mechanistic studies and DFT calculations showed that an in situ-formed borylcopper(I) species is responsible for the 1,2-addition (Scheme 73) [136]. C,O-Diboration of ketones 464 was explored using

Direct borylation of terrylene and quaterrylene

• Haruka Kano,
• Keiji Uehara,
• Kyohei Matsuo,
• Hironobu Hayashi,
• Hiroko Yamada and
• Naoki Aratani

Beilstein J. Org. Chem. 2020, 16, 621–627, doi:10.3762/bjoc.16.58

• fluorescence at 576 nm with a quantum yield of ΦF = 0.86 at 298 K (Figure 3). Both peaks are slightly red-shifted relative to those of intact terrylene (λabs = 560 nm and λem = 571 nm with ΦF = 0.82 in toluene). We employed density functional theory (DFT) and time-dependent (TD)-DFT calculations, both of them

• distributions is negligible because of the existence of node at 2,5,10,13-positions. The longest band of TB4 at 563 nm comprises the transition from equally destabilized HOMO (−4.29 eV) to LUMO (−1.99 eV) (oscillator strength, f = 0.86). The transition energies and oscillator strengths simulated by TD-DFT

• calculations showed a good agreement with the observed absorption spectra. Taking the successful result of the terrylene borylation, next we tried to perform the same reaction to quaterrylene (Scheme 2). The quaterrylene was prepared by the oxidative condensation reaction of perylene with TfOH and DDQ [9

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• , density functional theory (DFT) calculations were performed at the B3LYP/6-31G(d) level of theory. The a2-symmetry of the HOMOs and b2-symmetry of the LUMOs of each, the α- and β-ethynyl-substituted BODIPYs are almost identical to those of the unsubstituted compound 1a (Figure S24, Supporting Information

• , and DFT calculations. Supporting Information File 167: Crystallographic information file of compound 3a. Supporting Information File 168: Crystallographic information file of compound 6b. Acknowledgements We thank Dr. T. Ono at Kyushu University for the help of absolute photoluminescence quantum