Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• -raising activation (amine-based catalysis and N-heterocyclic carbenes), and iii) LUMO-lowering and HOMO-raising activation (bifunctional thioureas and squaramides). Due to the ubiquitous nature of non-covalent interactions in organic systems, they can play a decisive role in asymmetric transformations [15

• ]. Although quite important in all organocatalytic processes, there are specific organocatalysts which activate reactants through non-covalent interactions such as hydrogen bonding. These interactions are crucial to obtain high enantioselectivity in the reaction. The 1-azadienes possess an electronegative

• -unsaturated imines and variety of structures. The hetero-Diels–Alder and inverse electron demand hetero-Diels–Alder reactions. Different strategies to promote the activation of dienes and dienophiles in IEDADA reactions. Examples of non-covalent interactions in organocatalysis. Structure of a cinchona

Synthesis of the 1,5-disubstituted tetrazole-methanesulfonylindole hybrid system via high-order multicomponent reaction

• Cesia M. Aguilar-Morales,
• América A. Frías-López,
• Nadia V. Emilio-Velázquez,
• Alejandro Islas-Jácome,
• Angelica Judith Granados-López,
• Jorge Gustavo Araujo-Huitrado,
• Yamilé López-Hernández,
• Hiram Hernández-López,
• Luis Chacón-García,
• Jesús Adrián López and
• Carlos J. Cortés-García

Beilstein J. Org. Chem. 2024, 20, 3077–3084, doi:10.3762/bjoc.20.256

• combining the indole moiety with the 1,5-disusbtituted tetrazole pharmacophore could increase the non-covalent interactions, including π–π stacking, hydrogen bonding, and hydrophobic interactions. This combination may improve the pharmacodynamic profile, providing a solid foundation for developing compounds

Evaluating the halogen bonding strength of a iodoloisoxazolium(III) salt

• Dominik L. Reinhard,
• Anna Schmidt,
• Marc Sons,
• Julian Wolf,
• Elric Engelage and
• Stefan M. Huber

Beilstein J. Org. Chem. 2024, 20, 2401–2407, doi:10.3762/bjoc.20.204

• . Finally, the potential as halogen-bonding activator was benchmarked in solution in the gold-catalyzed cyclization of a propargyl amide. Keywords: diaryliodonium; gold catalysis; halogen bonding; hypervalent iodine; non-covalent interactions; Introduction The compound class of diaryliodonium (DAI) salts

Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis

• Stefan P. Schmid,
• Leon Schlosser,
• Frank Glorius and
• Kjell Jorner

Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196

• pitfall regarding computational data is its accuracy with respect to the ground truth, in particular for multiple factors relevant throughout catalysis, such as non-covalent interactions (NCIs) for organocatalysis or spin properties for transition metal catalysis [35][36]. While most quantities can in

• holistic investigations of algorithms and chemical representations. To summarise, the last decade has seen a steady refinement in the representation of chemical species, considering sterics, electronic properties and non-covalent interactions. Since these interactions are governing any reactivity, accurate

Factors influencing the performance of organocatalysts immobilised on solid supports: A review

• Zsuzsanna Fehér,
• Dóra Richter,
• Gyula Dargó and
• József Kupai

Beilstein J. Org. Chem. 2024, 20, 2129–2142, doi:10.3762/bjoc.20.183

• catalytic species. These methods can be classified into four categories: covalent bonding, non-covalent interactions (physisorption), ionic bonding, and encapsulation. The catalysts are connected to the support via strong chemical bonds in covalent bonding. In non-covalent interactions, the catalysts are

Regioselective alkylation of a versatile indazole: Electrophile scope and mechanistic insights from density functional theory calculations

• Pengcheng Lu,
• Luis Juarez,
• Paul A. Wiget,
• Weihe Zhang,
• Krishnan Raman and
• Pravin L. Kotian

Beilstein J. Org. Chem. 2024, 20, 1940–1954, doi:10.3762/bjoc.20.170

• other non-covalent interactions (NCIs) drive the N2-product formation. Methyl 1H-indazole-7-carboxylate (18) and 1H-indazole-3-carbonitrile (21) were also subjected to the reaction conditions and their mechanisms were evaluated. The N1- and N2-partial charges and Fukui indices were calculated for

• to be driven by stabilizing non-covalent interactions. Specifically, the carbonyl O in N2-s-cis shows NCIs with one of the benzene rings of PPh3 as well as a hydrogen bond-like NCI with a H-atom of the electrophilic methyl. Thus, the partitioning between transition states favor the N2-pathway over

A comparison of structure, bonding and non-covalent interactions of aryl halide and diarylhalonium halogen-bond donors

• Nicole Javaly,
• Theresa M. McCormick and
• David R. Stuart

Beilstein J. Org. Chem. 2024, 20, 1428–1435, doi:10.3762/bjoc.20.125

• Cl, Br, I, and At. We have used density functional theory (DFT) to uncover periodic trends in the orbitals used by the central halogen atom in forming covalent and non-covalent interactions and how this impacts the interatomic distance and energy of halogen-bond interactions (Scheme 1c). Results and

• observed for the cationic imidazolium series of XB donors 53–56 (Scheme 5, blue bars). The neutral monovalent XB donors 26–28 formed halogen-bonding complexes 42–44 with non-covalent interactions in all cases, even those with heavier halogen iodine and astatine (Scheme 5, orange bars). We turned our

Stability trends in carbocation intermediates stemming from germacrene A and hedycaryol

• Naziha Tarannam,
• Prashant Kumar Gupta,
• Shani Zev and
• Dan Thomas Major

Beilstein J. Org. Chem. 2024, 20, 1189–1197, doi:10.3762/bjoc.20.101

• ) basis set [33]. Additionally, to check the reliability of the energy calculations single point calculations were also performed with the larger def2-TZVPP [34] basis set for both functionals and to account for intramolecular non-covalent interactions, D3 dispersion corrections were added to the M06-2X

• ones presented here, and therefore were neglected. We used the non-covalent interactions (NCI) NCIplot analysis with the program NCIPLOT [39][40][41] to study the non-covalent interactions present in these molecules. To map local binding properties with this method, two scalar fields are used: the

• electron density (ρ) and the reduced-density gradient (RDG, s). The NCIplot provides qualitative information, and it can successfully map real-space regions where non-covalent interactions are prominent. The resulting plots have a color scheme of red–green–blue scale, where red represents attractive

Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis

• Zhiyong Yin and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67

• binding of both substrate surrogates to BaeJ-KS2, but it is unclear from these experiments, if 11 is bound covalently to the protein or through non-covalent interactions. To gain further evidence for the covalent binding of 11 to BaeJ-KS2, the highly conserved Cys residue involved in substrate attachment

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• that no new atoms are introduced into the molecule, thus ensuring first-order kinetics of the process without complexity. One of the possible mechanisms of redox-induced switching involves an intramolecular bond formation that introduces non-covalent interactions between tweezers endpoints leading to a

• electronic or geometrical properties upon oxidation or reduction. TTF and derivatives tweezers One of the most widely used electroactive moieties is tetrathiafulvalene (TTF). Its electron-donor π-system can form non-covalent interactions with various electron-poor π-systems, and those interactions can be

Enhanced host–guest interaction between [10]cycloparaphenylene ([10]CPP) and [5]CPP by cationic charges

• Eiichi Kayahara,
• Yoshiyuki Mizuhata and
• Shigeru Yamago

Beilstein J. Org. Chem. 2024, 20, 436–444, doi:10.3762/bjoc.20.38

• up new possibilities for the fabrication of supramolecular structures based on the non-covalent interactions using carbon nanorings [37][38]. Despite the unique structure of the host–guest complexes, however, their electronic structures are not very attractive. This is because the complex formation

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• remarkable advances not only highlighted the synthetic potential of photocatalysis but also served as inspiration for future developments of low-cost photocatalysis based on other non-covalent interactions. The simplicity, practicality, and broad substrate scope demonstrated by these approaches further

Complexes of resorcin[4]arene with secondary amines: synthesis, solvent influence on “in-out” structure, and theoretical calculations of non-covalent interactions

• Waldemar Iwanek

Beilstein J. Org. Chem. 2023, 19, 1525–1536, doi:10.3762/bjoc.19.109

• , finally, the structure with the lowest energy, with the functional PBE0-D4/mTZVPP/CPCM. The Hartree–Fock plus London dispersion (HFLD) method was used for the study of non-covalent interactions (NCI). The calculations lead to the conclusion that a reduction in electrostatic interactions and an increase in

• of non-covalent interactions within various types of supramolecular complexes [17]. One such method is HFLD [18], which can be considered a dispersion-corrected HF approach where the dispersion interaction between fragments is added at the DLPNO-CC level. The HFLD method demonstrates comparable

• performance to HF in terms of total interaction energies while maintaining the accuracy of DLPNO CCSD(T) [19]. This method proves very accurate in quantifying non-covalent interactions, such as those found in hydrogen-bonded systems, among others. Despite the relatively small cavity in the structure of

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• ). The authors’ explanation for the improved reactivity of o-anisyl derivative 39 was based on its improved solubility in dichloromethane. The contact distances were both within the Van der Waals radii criteria for confirming non-covalent interactions [33], which likely contributed to the ylide’s

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• (hydroxylation, hydroperoxidation, halogenation, etc.), cross-dehydrogenative coupling and oxidative cyclization, alcohol oxidation, and the oxidation of other functional groups. Compared to other types of organocatalysis (type I and type II in Scheme 1) reversible bonding and non-covalent interactions of redox

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• base platform creates an optimal balance between the covalent binding with the substrate (which does not “kill” its reactivity but precludes its redox destruction) with non-covalent interactions in the metal chiral coordination environment governing the reaction’s stereocontrol. Cyclic voltammograms

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• be performed. Supramolecular systems based on non-covalent interactions have drawn considerable attention in assembling efficient light harvesting systems (LHSs) in the last decade [60][61]. Significant attention has been centered to construct artificial LHSs via FRET (fluorescence resonance energy

Recent advances in organocatalytic asymmetric aza-Michael reactions of amines and amides

• Pratibha Sharma,
• Raakhi Gupta and
• Raj K. Bansal

Beilstein J. Org. Chem. 2021, 17, 2585–2610, doi:10.3762/bjoc.17.173

• overviews the literature published during the last 10 years concerning the asymmetric aza-MR of amines and amides catalysed by organocatalysts. Both types of the organocatalysts, i.e., those acting through non-covalent interactions and those working through covalent bond formation have been applied for the

Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies

• Alexander Zika and
• Franziska Gröhn

Beilstein J. Org. Chem. 2021, 17, 166–185, doi:10.3762/bjoc.17.17

• molecular recognition processes have been established based on different non-covalent interactions such as hydrogen bonding [9][10][11][12], π–π interaction [13][14][15][16][17], hydrophobic effects, and amphiphilicity [18][19][20][21]. It has been highly desirable to establish concepts that could be

Tuning the solid-state emission of liquid crystalline nitro-cyanostilbene by halogen bonding

• Subrata Nath,
• Alexander Kappelt,
• Matthias Spengler,
• Bibhisan Roy,
• Jens Voskuhl and
• Michael Giese

Beilstein J. Org. Chem. 2021, 17, 124–131, doi:10.3762/bjoc.17.13

• tuning of the fluorescence behaviour and mesomorphic properties of the assemblies. Keywords: fluorescence; halogen bonding; liquid crystal; Introduction Supramolecular chemistry has proven to be an efficient approach for the development of novel smart materials, since it relies on non-covalent

• interactions, which allow for dynamic responses to external stimuli [1]. In addition, the self-assembly of the complementary molecular entities provides an easy access to functional systems and enables recyclability and self-healing properties of the materials [2]. With respect to the formation of

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

• vibrational modes of the molecule. Especially for non-covalent interactions such as hydrogen bonding, vibrational spectroscopy has been shown to be very sensitive [10][11]. In the context of supramolecular recognition, for example, IR spectroscopy has been applied to monitor the binding of tetrapeptides by

• -covalent interactions namely hydrogen bonds, van der Waals, and/or hydrophobic interactions [1][2][3][4][5]. In this context, Schmuck and co-workers have introduced a class of synthetic receptors based on the guanidiniocarbonyl pyrrole (GCP) moiety (cf. Figure 1 top right) as a carboxylate binding site

• 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

NMR Spectroscopy of supramolecular chemistry on protein surfaces

• Peter Bayer,
• Anja Matena and
• Christine Beuck

Beilstein J. Org. Chem. 2020, 16, 2505–2522, doi:10.3762/bjoc.16.203

• steric accessibility is an important determining factor for calixarene binding, the overall local electrostatic potential of the protein surface as well as other non-covalent interactions such as hydrophobic interactions or aromatic ring stacking contribute to a certain selectivity for some lysine

• in the crystal structures, which enable a greater diversity of non-covalent interactions with the protein and even different binding modes on the same lysine side chain. With increasing ring size, the calixarenes promote ligand-induced ordered multimerization of proteins. Cyt c for example is

Naphthalene diimide bis-guanidinio-carbonyl-pyrrole as a pH-switchable threading DNA intercalator

• Poulami Jana,
• Filip Šupljika,
• Carsten Schmuck and
• Ivo Piantanida

Beilstein J. Org. Chem. 2020, 16, 2201–2211, doi:10.3762/bjoc.16.185

• energetically favourable non-covalent interactions, hydrogen bonds, and van der Waals interactions formed between the DNA/RNA and solvent, and between the compound 4 and solvent. The large positive entropy changes suggest solvent release upon binding, which makes a favourable contribution to the reaction Gibbs

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

• ; Introduction The interplay of non-covalent interactions between nucleic acids and proteins or peptides is the basis of life and is also often used for the design of artificial small molecules, aiming for sensing or control of biorelevant processes. Many naturally occurring bioactive molecules contain a short

Models of necessity

• Timothy Clark and
• Martin G. Hicks

Beilstein J. Org. Chem. 2020, 16, 1649–1661, doi:10.3762/bjoc.16.137

• ideas about chemical structures and reactions. This early extension of the Lewis model and the introduction of two-center three-electron bonding [44] serve as prototypes for what will become necessary improvements to handle in particular non-covalent interactions but in general any structures or

• ] or quantitative VB calculations. If we delve deeper, we find MO interpretations of, for instance, non-covalent interactions [82] coexisting with more fundamentally physical electrostatic pictures [83]. Indeed, the polarization/charge transfer shown in Figure 4 is often interpreted as donation into an

• reactions. There is, however, a need to add non-covalent interactions to the model in order to take the importance of complexation and aggregation via non-covalent interactions into account. This could be done in a purely ad hoc fashion for each type of interaction. This is how force-field developers have