Total synthesis of a Streptococcus pneumoniae serotype 12F CPS repeating unit hexasaccharide

• Peter H. Seeberger,
• Claney L. Pereira and
• Subramanian Govindan

Beilstein J. Org. Chem. 2017, 13, 164–173, doi:10.3762/bjoc.13.19

• participation groups and solvent effects. It lends further credence to the linear assembly concept in which one monosaccharide unit at a time is incorporated, and which serves as the basis for automated glycan assembly [43]. With the synthetically sourced hexasaccharide repeating unit in hand detailed

Methylenelactide: vinyl polymerization and spatial reactivity effects

• Judita Britner and
• Helmut Ritter

Beilstein J. Org. Chem. 2016, 12, 2378–2389, doi:10.3762/bjoc.12.232

• ) = 2914 cm−1). Figure 4 shows the IR spectra of MLA and of the obtained poly(MLA). To evaluate some kinetic solvent effects of the discussed self-initiated polymerization reactions of MLA, the kinetics of the AIBN-initiated and initiator-free radical polymerizations of MLA were repeated in less polar 1,4

Experimental and theoretical investigations into the stability of cyclic aminals

• Edgar Sawatzky,
• Antonios Drakopoulos,
• Martin Rölz,
• Christoph Sotriffer,
• Bernd Engels and
• Michael Decker

Beilstein J. Org. Chem. 2016, 12, 2280–2292, doi:10.3762/bjoc.12.221

• cc-PVTZ basis sets [42][43] and all computations were performed with TURBOMOLE [44]. Solvent effects were mimicked by the Screening Model (COSMO) for water [45]. As expected, N-3 was found to be more basic for all test compounds, with the exception of 9c. Therefore, in the following text, only the

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

• David R. Chisholm,
• Garr-Layy Zhou,
• Ehmke Pohl,
• Roy Valentine and
• Andrew Whiting

Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174

• route for the synthesis of 20a. Synthesis of THQ 21 and DHQ 22 using borane·dimethyl sulphide complex or DIBAL, respectively. Postulated mechanism for the formation of 22 using DIBAL. Miyaura borylation of 21 and 22 to give crystalline boronic esters 29 and 30. Temperature and solvent effects from the

One-pot synthesis of tetracyclic fused imidazo[1,2-a]pyridines via a three-component reaction

• Bo Yang,
• Chuanye Tao,
• Taofeng Shao,
• Jianxian Gong and
• Chao Che

Beilstein J. Org. Chem. 2016, 12, 1487–1492, doi:10.3762/bjoc.12.145

• % yield. Performing the reaction under reflux conditions slightly improved the yield to 11%. We next examined solvent effects in this MCR reaction and various solvents were screened, as summarized in Table 1. We observed that protic solvents with medium polarity can facilitate the reaction by product

Chiral cyclopentadienylruthenium sulfoxide catalysts for asymmetric redox bicycloisomerization

• Barry M. Trost,
• Michael C. Ryan and
• Meera Rao

Beilstein J. Org. Chem. 2016, 12, 1136–1152, doi:10.3762/bjoc.12.110

• ligands. Solvent effects on asymmetric redox bicycloisomerization reaction as described in [43]. Effect of the catalyst structure on the redox bicycloisomerization as described in [43]. Comparison of complex 1 to other catalyst systems as described in [43]. Effect of the nitrogen protecting group on

The role of alkyl substituents in deazaadenine-based diarylethene photoswitches

• Christopher Sarter,
• Michael Heimes and
• Andres Jäschke

Beilstein J. Org. Chem. 2016, 12, 1103–1110, doi:10.3762/bjoc.12.106

• the differences between the one- and two-methyl switches are not due to solvent effects. This latter observation already indicated poor reversibility and fatigue resistance for the one-methyl switches. We therefore undertook absorption measurements over multiple cycles of ring closure by UV and ring

Strecker degradation of amino acids promoted by a camphor-derived sulfonamide

• M. Fernanda N. N. Carvalho,
• M. João Ferreira,
• Ana S. O. Knittel,
• Maria da Conceição Oliveira,
• João Costa Pessoa,
• Rudolf Herrmann and
• Gabriele Wagner

Beilstein J. Org. Chem. 2016, 12, 732–744, doi:10.3762/bjoc.12.73

• Table 1. The calculated activation energies are of course not to be taken literally, since solvent effects were not included, nor was a basis set for superposition error correction applied. We use these calculated values for excluding high-energy pathways, and consider a threshold limit (≈40 kcal/mol

Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career

• Eric V. Anslyn

Beilstein J. Org. Chem. 2016, 12, 362–376, doi:10.3762/bjoc.12.40

• appropriate for the job: valve spring compressors, feeler gauges, socket wrenches, etc. As organic chemists, we propose hypotheses explaining how Mother Nature works, and we have particular experimental tools to test our theories: kinetics, isotope effects, solvent effects, etc. [24]. Reactions with multiple

Enabling technologies and green processes in cyclodextrin chemistry

• Giancarlo Cravotto,
• Marina Caporaso,
• Laszlo Jicsinszky and
• Katia Martina

Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30

• transition state [87]. Solvent effects and ion pair formation are critical to the mechanism of SN1 reactions meaning that this mechanism is usually restricted in HSBM reactions. While solid-state intermolecular SN2 reactions depend on contact between interacting particles only, SN1 reactions may show more

• milling conditions favours SN2 reactions; however it is also true that a solventless environment does not necessarily mean that there is a lack of solution in a liquid phase. Some reaction mixture components can often be liquid, while solvent effects or mixed SN2 and SN1-type reaction mechanisms cannot be

Simple activation by acid of latent Ru-NHC-based metathesis initiators bearing 8-quinolinolate co-ligands

• Julia Wappel,
• Roland C. Fischer,
• Luigi Cavallo,
• Christian Slugovc and
• Albert Poater

Beilstein J. Org. Chem. 2016, 12, 154–165, doi:10.3762/bjoc.12.17

• Gaussian) using the M06 functional [73]. Solvent effects, dichloromethane, were calculated with the PCM model [74][75], and non-electrostatic terms were also included. The geometry optimizations were performed without symmetry constraints, and the nature of the extrema was checked by analytical frequency

A journey in bioinspired supramolecular chemistry: from molecular tweezers to small molecules that target myotonic dystrophy

• Steven C. Zimmerman

Beilstein J. Org. Chem. 2016, 12, 125–138, doi:10.3762/bjoc.12.14

• host–guest chemistry [33]. Perry Corbin, Steven Dell, and I were pleased to work with Frank Klärner and his group on linking a host analogous to 20 to silica and to study the solvent effects on host–guest complexation chemistry using our HPLC method [34]. Many of the molecular tweezers described above

Versatile deprotonated NHC: C,N-bridged dinuclear iridium and rhodium complexes

• Albert Poater

Beilstein J. Org. Chem. 2016, 12, 117–124, doi:10.3762/bjoc.12.13

• functional [82]. Solvent effects, using either tetrahydrofuran, dichloromethane or toluene, were calculated with the polarizable continuous solvation model polarizable continuum model (PCM) model [83][84], and non-electrostatic terms were also included. The cavity is created via a series of overlapping

A comprehensive study of olefin metathesis catalyzed by Ru-based catalysts

• Albert Poater and
• Luigi Cavallo

Beilstein J. Org. Chem. 2015, 11, 1767–1780, doi:10.3762/bjoc.11.192

• and side, respectively. Next, by means of DFT calculations Goddard and co-workers indicated clearly that solvent effects were of paramount relevance to the relatively high stability of b [48], while in the gas phase structure a was much favored [13]. Moreover, Grubbs and co-workers reported the X-ray

• equilibrium is based on a delicate balance between electronic, steric, and solvent effects. Particularly sterically demanding substituents of the NHC and bulky olefins clearly favor the side reaction pathway. Moreover this study corroborated the validity of BP86 for these second generation Grubbs catalysts

• performed without symmetry constraints, and the nature of the extrema was checked by analytical frequency calculations. Furthermore, all extrema were confirmed by calculation of the intrinsic reaction paths. The energies discussed throughout the text contain ZPE corrections. Solvent effects including

Consequences of the electronic tuning of latent ruthenium-based olefin metathesis catalysts on their reactivity

• Karolina Żukowska,
• Eva Pump,
• Aleksandra E. Pazio,
• Krzysztof Woźniak,
• Luigi Cavallo and
• Christian Slugovc

Beilstein J. Org. Chem. 2015, 11, 1458–1468, doi:10.3762/bjoc.11.158

• conducted by BP86//SVP, solvent effects were added by single point calculations using M06//TZVP functional (cf. Supporting Information File 1). The first question tackled concerned the anticipated coordination of the carbonyl group in compound 15 to form the corresponding 18-electron complex. Formation of

• (orange). Energy profile of trans–cis isomerization, modelled in CH2Cl2, (ΔE in kcal/mol). Geometry optimizations BP86//SVP, solvent effects included by single point calculations, using M06//TZVP. Time/conversion plots for the transformation of 16 catalyzed by 5 mol % of the trans isomers of trans-5a, 14

Antioxidant potential of curcumin-related compounds studied by chemiluminescence kinetics, chain-breaking efficiencies, scavenging activity (ORAC) and DFT calculations

• Adriana K. Slavova-Kazakova,
• Silvia E. Angelova,
• Timur L. Veprintsev,
• Petko Denev,
• Davide Fabbri,
• Maria Antonietta Dettori,
• Maria Kratchanova,
• Vladimir V. Naumov,
• Aleksei V. Trofimov,
• Rostislav F. Vasil’ev,
• Giovanna Delogu and
• Vessela D. Kancheva

Beilstein J. Org. Chem. 2015, 11, 1398–1411, doi:10.3762/bjoc.11.151

• the kinetic solvent effect of water is of great importance in this case. Hydrogen bonding can have a profound influence on the activity of phenols as antioxidants. It is generally recognized [28][29][30] that solvent effects and especially the ionization effect of the medium may alter the mechanism of

Surprisingly facile CO₂ insertion into cobalt alkoxide bonds: A theoretical investigation

• Willem K. Offermans,
• Claudia Bizzarri,
• Walter Leitner and
• Thomas E. Müller

Beilstein J. Org. Chem. 2015, 11, 1340–1351, doi:10.3762/bjoc.11.144

• (III)–salen complexes are related. Solvent effects were not considered in the present study. The tri-coordinated di-iminate zinc–alkoxide complex [(BDI)ZnOCH3]. The [(2-hydroxyethoxy)CoIII(salen)(L)] complex chosen as catalyst model for the calculations; 1: R1–6 = H; 1a: = -C4H8-, R3–6 = H; 1b

Properties of PTFE tape as a semipermeable membrane in fluorous reactions

• Brendon A. Parsons,
• Olivia Lin Smith,
• Myeong Chae and
• Veljko Dragojlovic

Beilstein J. Org. Chem. 2015, 11, 980–993, doi:10.3762/bjoc.11.110

• dichlormethane as a solvent (Scheme 1 and Figure 8). Solvent-assisted transport through PTFE tape In the earlier work we reported that PTFE tape is impermeable to dimethyl phthalate [21]. However, we suspected that solvent effects may alter the permeability of PTFE tape even when it is otherwise impermeable to a

First principle investigation of the linker length effects on the thermodynamics of divalent pseudorotaxanes

• Andreas J. Achazi,
• Doreen Mollenhauer and
• Beate Paulus

Beilstein J. Org. Chem. 2015, 11, 687–692, doi:10.3762/bjoc.11.78

• ; Gibbs energy; pseudorotaxanes; solvent effects; COSMO-RS; Introduction If two or more binding sites of a molecular system are involved in the association process, the interaction energy can be significantly increased compared to the sum of the individual binding energies. This effect is called

• contributions, enthalpic and entropic temperature effects as well as solvent effects are included in our simulations in order to compare to experimentally obtained Gibbs energy of association. Results and Discussion In order to investigate the cooperativity effects of the binding between divalent host molecules

• temperature or solvent effects. Including the counter ion in the determination of ΔG has a much weaker effect in the divalent case compared to the monovalent one, because the guest molecule is larger and the positive charge of the amide group can be distributed better over the molecule. For the divalent

Synthesis and properties of novel star-shaped oligofluorene conjugated systems with BODIPY cores

• Clara Orofino-Pena,
• Diego Cortizo-Lacalle,
• Joseph Cameron,
• Muhammad T. Sajjad,
• Pavlos P. Manousiadis,
• Neil J. Findlay,
• Alexander L. Kanibolotsky,
• Dimali Amarasinghe,
• Peter J. Skabara,
• Tell Tuttle,
• Graham A. Turnbull and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2704–2714, doi:10.3762/bjoc.10.285

• red region of the spectrum. DFT calculations The structures of T-B1 and Y-B1 were optimised using the program Gaussian 09 [38] with the CAM-B3LYP [39] functional and the TZVP [40] basis set. Solvent effects were considered with the inclusion of the SMD [41] solvent model. In order to increase the

Photorelease of phosphates: Mild methods for protecting phosphate derivatives

• Sanjeewa N. Senadheera,
• Abraham L. Yousef and
• Richard S. Givens

Beilstein J. Org. Chem. 2014, 10, 2038–2054, doi:10.3762/bjoc.10.212

• competition for incident radiation by the unrearranged byproduct chromophore 12 or 15. The role of H2O and hydroxylic solvents observed in this series is in complete accord with solvent effects on the parent pHP photoreactions [6][13][15][40][41][42][43][44][45][46]. The photo-Favorskii reaction (Scheme 7) is

Substitution effect and effect of axle’s flexibility at (pseudo-)rotaxanes

• Friedrich Malberg,
• Jan Gerit Brandenburg,
• Werner Reckien,
• Oldamur Hollóczki,
• Stefan Grimme and
• Barbara Kirchner

Beilstein J. Org. Chem. 2014, 10, 1299–1307, doi:10.3762/bjoc.10.131

• . Solvent effects As expected, the presence of the solvent decreases the binding energy by 11–14 kcal/mol, see Table 4. Even though the trends in the difference between single and double bond binding energy is constantly 1–4 kcal/mol. By comparison of the total energies of the complex, separated wheel, and

cis–trans Isomerization of silybins A and B

• Michaela Novotná,
• Radek Gažák,
• David Biedermann,
• Florent Di Meo,
• Petr Marhol,
• Marek Kuzma,
• Lucie Bednárová,
• Kateřina Fuksová,
• Patrick Trouillas and
• Vladimír Křen

Beilstein J. Org. Chem. 2014, 10, 1047–1063, doi:10.3762/bjoc.10.105

• energies, including the zero-point correction (V), enthalpies (H) and Gibbs energies (G) at 298 K of the reactants, intermediates and products were determined at the (U)B3P86/6-31+G(d,p) level, well-adapted for polyphenol reactivity. Solvent effects were implicitly taken into account by using a PCM

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

• desired DKPs products 168 in good to excellent yields (53–72%). Solvent effects of the Ugi reaction under microwave irradiation were considered by Santra and Andreana (Scheme 53) [146]. Protic solvents such as water gave rise to either 2.5-diketopiperazines 170 via an aza-Micheal reaction or 2-azaspiro

3-Pyridinols and 5-pyrimidinols: Tailor-made for use in synergistic radical-trapping co-antioxidant systems

• Luca Valgimigli,
• Daniele Bartolomei,
• Riccardo Amorati,
• Evan Haidasz,
• Jason J. Hanthorn,
• Susheel J. Nara,
• Johan Brinkhorst and
• Derek A. Pratt

Beilstein J. Org. Chem. 2013, 9, 2781–2792, doi:10.3762/bjoc.9.313

• . ArOH). Relevant reactions in co-antioxidant systems. Model for kinetic solvent effects on the radical-trapping activity of phenolic antioxidants. Rate constants for the reactions of 4–12 with peroxyl radicals (kinh) at 303 K obtained from AIBN-initiated inhibited autoxidations of styrene (50% v/v) in