Electron-rich triarylphosphines as nucleophilic catalysts for oxa-Michael reactions

• Susanne M. Fischer,
• Simon Renner,
• A. Daniel Boese and
• Christian Slugovc

Beilstein J. Org. Chem. 2021, 17, 1689–1697, doi:10.3762/bjoc.17.117

• TURBOMOLE program (version 7.4.1) [43]. Geometries were pre-optimized using the PBE [44] functional, the def2-SVPD [45][46] basis set and D3 [47] dispersion correction. All structures were then re-optimized using the hybrid functional B3LYP [48][49][50][51] D3 with the def2-TZVPPD basis set. For gas-phase

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

Chiral isothiourea-catalyzed kinetic resolution of 4-hydroxy[2.2]paracyclophane

• David Weinzierl and
• Mario Waser

Beilstein J. Org. Chem. 2021, 17, 800–804, doi:10.3762/bjoc.17.68

• ) via gas phase pyrolysis of para-xylene in 1949 [5]. Over the years, these compounds established themselves as a unique class of “bent and battered” [6] strained molecules with remarkable chemical and physical properties [1][2][3][4][7][8][9]. Besides their potential applications in material and

Breakdown of 3-(allylsulfonio)propanoates in bacteria from the Roseobacter group yields garlic oil constituents

• Anuj Kumar Chhalodia and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 569–580, doi:10.3762/bjoc.17.51

• preferred gas-phase reaction. The ecology of marine bacteria in their interaction with algae is particularly interesting in which the bacteria can promote the algal growth, but can also kill their host [10][11]. For both processes, the phytohormone indole-3-acetic acid is used as a messenger molecule [10

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

• -substituent (i.e., H, CH3, or CF3) would have a poor impact. Gas phase calculations by Tsuno et al. provided evidence for the significantly increased resonance stabilization contribution in 14f↔14f’ (r = 1.4) relative to the t-cumyl cation 57 (r = 1.0) [69]. α-(Trifluoromethyl)heteroarylcarbenium ions The

The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

• : Hexafluoropropylene oxide (HFPO, 41) is an effective and cheap reagent for the difluorocyclopropanation of simple alkyl- and aryl-substituted alkenes [52]. It undergoes decomposition to form difluorocarbene (Scheme 16) at temperatures above 170 °C either under autoclave conditions or by gas-phase co-pyrolysis [53

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

• , respectively. The compounds 2CzCF3, 2CzSCF3, and 2CzSF5, from Type I molecules, show significant promise as deep blue TADF emitters, possessing high calculated singlet energies in the gas phase (3.62 eV, 3.66 eV, and 3.51 eV, respectively) and small, ΔESTs, of 0.17 eV, 0.22 eV, and 0.07 eV, respectively. For

• calculated in gas phase in this work), which was reported as deep blue emitter with λEL = 418 nm and CIE coordinate of (0.15, 0.05) when doped in DPEPO [21]. DFT calculations for 5CzOCF3, 5CzSCF3, and 5CzSF5 predicted dense populations of excited states between T1 and S1, which should assist in rISC process

• [28][29]. Results and Discussion We employed density functional theory (DFT) and TD-DFT calculations to predict the photophysical properties of these emitters in order to assess their potential as TADF emitters for OLEDs. All ground-state calculations were performed using PBE0/6-31G(d,p) in the gas

Semiautomated glycoproteomics data analysis workflow for maximized glycopeptide identification and reliable quantification

• Steffen Lippold,
• Arnoud H. de Ru,
• Jan Nouta,
• Peter A. van Veelen,
• Magnus Palmblad,
• Manfred Wuhrer and
• Noortje de Haan

Beilstein J. Org. Chem. 2020, 16, 3038–3051, doi:10.3762/bjoc.16.253

• ). The y- and Y-fragment ions of (glyco)peptides with Cys oxidation showed a characteristic neutral loss of 107.0041 Da (C2H5O2NS), as reported for singly oxidized carbamidomethylated Cys through an elimination reaction in the gas phase (Figures S13 and S16–S18, Supporting Information File 2) [27

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

• –vis spectrometer (Perkin-Elmer Lambda 650) where liquid samples were kept in 2 mm fused silica cuvettes (Hellma). DFT calculations were performed with the Gaussian 16 program package [25]. The molecule was calculated in the gas phase in its protonated form with one positive net charge. The resulting

A heterobimetallic tetrahedron from a linear platinum(II)-bis(acetylide) metalloligand

• Matthias Hardy,
• Marianne Engeser and
• Arne Lützen

Beilstein J. Org. Chem. 2020, 16, 2701–2708, doi:10.3762/bjoc.16.220

• succeed to obtain single crystals of our metallosupramolecular assemblies that were suitable for single-crystal X-ray diffraction experiments. Therefore, we generated energy-minimized gas phase structures of 4, employing a force-field approach using the GFN2-xTB approach recently established to model

• equivalent positions of P atoms. Detailed excerpt of the 31P NMR spectrum of 4 (202 MHz, acetonitrile-d3, 298 K). 1H NMR and DOSY spectrum of heterobimetallic assembly 4 (500 MHz, acetonitilre-d3, 298 K). GFN2-xTB minimized gas phase models of the cationic units of all possible diastereomers of 4. Color code

Activation of pentafluoropropane isomers at a nanoscopic aluminum chlorofluoride: hydrodefluorination versus dehydrofluorination

• Maëva-Charlotte Kervarec,
• Thomas Braun,
• Mike Ahrens and
• Erhard Kemnitz

Beilstein J. Org. Chem. 2020, 16, 2623–2635, doi:10.3762/bjoc.16.213

• pentafluoropropanes (HFC-245 isomers) using chromia-based catalysts, or metal chloride/fluoride (AlF3, MgF2)-supported catalysts at elevated temperatures (350 °C) [11][14][15][17][18]. The group of Lu recently reported the gas-phase transformation of 1,1,1,3,3-pentafluoropropane (HFC-245eb) into 1,3,3,3

Dawn of a new era in industrial photochemistry: the scale-up of micro- and mesostructured photoreactors

• Emine Kayahan,
• Mathias Jacobs,
• Leen Braeken,
• Leen C.J. Thomassen,
• Simon Kuhn,
• Tom van Gerven and
• M. Enis Leblebici

Beilstein J. Org. Chem. 2020, 16, 2484–2504, doi:10.3762/bjoc.16.202

• using a spray system. The catalyst reactivity in the NETmix reactor was 70 times higher than for the monolithic photoreactor [62]. When the reactions involve a gas phase, a Taylor flow, also known as a slug flow, is commonly utilized in microstructured reactors. Su et al. studied the intrinsic kinetics

• ), and C is the concentration of the attenuating species (mol⋅m−3). Photoreactions are often heterogeneous, with solid particles in the reaction medium. In addition, some photoreactions contain a gas phase, which further complicates light field models. For heterogeneous photoreactions, the liquid

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

• geometry is quite similar among the three conformers. Only for Iga, where the gauche fluorine atom points to the opposite direction of the amine group, the triazole ring was farther away from the 1,2-disubstituted ethane moiety. Note that the gas-phase relative conformational energy ΔE increases, i.e

• the next section) and is naturally more stabilized by polar solvents. Therefore, further analysis will consider the gas phase, since in this way we are accounting for the intrinsic intramolecular interactions without the influence of solvent as an external factor. To better understand the relative

• known in the literature [23] and, accordingly, it differs from the energy minimum conformations computed in this work. However, a conformational search in the gas phase, as performed herein, is necessary to fully understand the intramolecular interactions and to establish the correlation between μ and

A proposed sustainability index for synthesis plans based on input provenance and output fate: application to academic and industrial synthesis plans for vanillin as a case study

• John Andraos

Beilstein J. Org. Chem. 2020, 16, 2346–2362, doi:10.3762/bjoc.16.196

• environmental and safety-hazard impacts of reactants and reagents become important since reaction solvent usage dramatically decreases. Reactions involving first generation feedstocks are typically gas-phase reactions run without any reaction solvent. However, as the synthesis chain extends to more complex

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

• were calculated by Density Functional Theory at the B3LYP/6-31+G(d,p) level of theory in the gas phase [64][65]. This method was also applied to study the nonlinear optic (NLO) properties of the dyes in their ground states. The theoretical absorption spectra in different solvents were calculated using

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

• and geometry optimizations. Ho and co-worker showed that the use of the lowest-energy conformations as calculated in the respective solvents gave more accurate lipophilicities than the use of the lowest energy conformations in the gas phase [36]. Somewhat surprisingly, implicit solvent models proved

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

• . The further investigation of the potential energy surfaces associated with two possible channels leading to oxazolidinones and five-membered cyclic carbonates disclosed that the cycloaddition reaction proceeds via an asynchronous concerted mechanism in gas phase and in DCM. Keywords: chlorosulfonyl

• N4 onto the less sterically encumbered C1 atom of the epoxide 7f forming intermediate 11. Optimized geometries of transition structures are depicted in Figure 1. Our calculated results for the reaction indicate 17.4 kcal/mol (gas phase) and 26.7 kcal/mol (in DCM) preference for the TS1 over the TS1

• energy profiles connecting each transition state to the two associated minima. The effect of the solvent environment on the reaction pathways has been taken into account by single-point energy calculations on the gas-phase stationary points using a polarizable continuum model (PCM) [64] at M06-2X/6-31+G

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

Activated carbon as catalyst support: precursors, preparation, modification and characterization

• Melanie Iwanow,
• Tobias Gärtner,
• Volker Sieber and
• Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

• . Different methods can be used for the measurements. The volumetric method with determination of the gas removed from the gas phase and the gravimetric method, where the uptake of the gas by the adsorbent is determined by the increase in mass. In addition, static or dynamic techniques are available for the

• -containing surface groups on the activated carbon materials. They could observe that gas phase oxidation led to a higher amount of mainly hydroxy and carbonyl groups, whereas liquid phase treatment with nitric acid results in an increase of carboxylic acid groups [110]. Lillo-Ródenas et al. used TPD for the

A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium

• Shun Saito,
• Kota Atsumi,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Naoya Oku,
• Md. Rokon Ul Karim,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1100–1110, doi:10.3762/bjoc.16.97

• structures 1a and 1b The conformational search on structure 1a began by applying 100,000 steps of the Monte-Carlo Multiple Minimum (MCMM) method with PRCG energy minimization using the OPLS3e force field (gas phase) to obtain 20 conformational isomers within 5.0 kcal/mol from the minimum energy conformer

Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin: experimental and computational evidence for intramolecular and intermolecular C–F···H–C bonds

• Vuyisa Mzozoyana,
• Fanie R. van Heerden and
• Craig Grimmer

Beilstein J. Org. Chem. 2020, 16, 190–199, doi:10.3762/bjoc.16.22

• H3···19F coupling (Figure 3). Evidence of a HOESY interaction between H5···19F and H3···19F indicates that neither the H3···19F nor the H5···19F interaction limits the C4–C1′ bond rotation. The geometry of coumarin 6 (single molecule, gas phase) was optimized using the B3LYP functional and the 6-311G

• angle Φ C2’–C1’–C4–C4a (°). Short contacts within the single-crystal X-ray structure of coumarin 6. Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin (6). Experimental and theoretical (gas phase) 1H and 13C chemical shift (δ) for atoms within six bonds from fluorine for coumarin 6 and RSMD values

The reaction of arylmethyl isocyanides and arylmethylamines with xanthate esters: a facile and unexpected synthesis of carbamothioates

• Narasimhamurthy Rajeev,
• Toreshettahally R. Swaroop,
• Ahmad I. Alrawashdeh,
• Shofiur Rahman,
• Abdullah Alodhayb,
• Seegehalli M. Anil,
• Kuppalli R. Kiran,
• Chandra,
• Paris E. Georghiou,
• Kanchugarakoppal S. Rangappa and
• Maralinganadoddi P. Sadashiva

Beilstein J. Org. Chem. 2020, 16, 159–167, doi:10.3762/bjoc.16.18

• with Gaussian 09 [36]. The HF/6-31G(d) level of theory in the gas phase was only used to locate the transition state geometries. An intrinsic reaction coordinate (IRC) analysis was conducted for each transition state studied in this work to confirm that the transition states were associated with the

Understanding the role of active site residues in CotB2 catalysis using a cluster model

• Keren Raz,
• Ronja Driller,
• Thomas Brück,
• Bernhard Loll and
• Dan T. Major

Beilstein J. Org. Chem. 2020, 16, 50–59, doi:10.3762/bjoc.16.7

• active site cluster model. The results revealed the significant effect of the active site residues on the relative electronic energy of the intermediates and transition state structures with respect to gas phase data. A detailed understanding of the role of the enzyme environment on the CotB2 reaction

• ]. Theoretical quantum mechanical (QM) investigations on the chemistry of terpenes in the gas phase have provided a detailed understanding of the carbocation mechanisms underlying terpene synthase function [25][26][27]. Further, we have used multiscale modeling tools to study the effects of the enzyme

• cyclopropylcarbinyl cation, as shown by isotope labeling [41]. QM calculations support this unusual 1,3-alkyl shift that interconverts H and I [38][39]. Finally, the cyclopropyl ring opens by virtue of a nucleophilic water attack, and cyclooctat-9-en-7-ol is formed. Although gas phase calculations shed light on the

Two new aromatic polyketides from a sponge-derived Fusarium

• Mada Triandala Sibero,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Ocky K. Karna Radjasa,
• Agus Sabdono,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2941–2947, doi:10.3762/bjoc.15.289

• Supporting Information File 2. Computational search and NMR calculations of structures a and b The conformational search on structure a began by applying 100,000 steps of the Monte-Carlo Multiple Minimum (MCMM) method with PRCG energy minimization using the OPLS3e force field (gas phase) to obtain 42

Synthesis and optoelectronic properties of benzoquinone-based donor–acceptor compounds

• Daniel R. Sutherland,
• Nidhi Sharma,
• Georgina M. Rosair,
• Ifor D. W. Samuel,
• Ai-Lan Lee and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2019, 15, 2914–2921, doi:10.3762/bjoc.15.285

• carbazoles with respect to the bridging benzene of ca. 44° in both 3 and 4 (Figure 2). Theoretical properties Density functional theory (DFT) calculations were performed in the gas phase to assess the electronic structures of 2–5 (see Supporting Information File 1 for details). The S1 and T1 excited states