What defines electrophilicity in carbonyl compounds

Chemical Science, Journal Year: 2024, Volume and Issue: 15(11), P. 3980 - 3987

Published: Jan. 1, 2024

The origin of the electrophilicity a series cyclohexanones and benzaldehydes is investigated using activation strain model quantitative Kohn–Sham molecular orbital (MO) theory.

Language: Английский

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Acidity of Isomorphic Substituted Zeolites with B, Al and Ga Revisited

ChemPhysChem, Journal Year: 2024, Volume and Issue: 25(9)

Published: Feb. 14, 2024

Abstract Isomorphic substitution of zeolites with B, Al and Ga is a widely used approach in catalysis. The experimentally reported trend their acidities decreases the order: Al>Ga>B. However, consistent explanation still lacking literature. To bring more understanding this trend, density functional theory computations were conducted on several model systems. First, acidity small clusters two (2T) five (5T) tetrahedral sites was analyzed. These systems then projected onto three large void structures: H‐[A]‐BEA (52T), H‐[A]‐FAU (84T) H‐[A]‐MOR (112T) A=B, Al, Ga. Our electron Interacting Quantum Atom analyses show that originates from much stronger O−Al bond, which dominated by electrostatic attraction. bridging hydroxyl therefore donates charge to metal, proton becomes positive consequently acidic. are acidic than B due greater covalent nature O−Ga bond. resulting acidity, as seen ammonia, depends both oxygen distribution surrounding oxygens exerted substituents.

Language: Английский

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Computational Organic Chemistry: The Frontier for Understanding and Designing Bioorthogonal Cycloadditions

Topics in Current Chemistry, Journal Year: 2024, Volume and Issue: 382(2)

Published: May 10, 2024

Computational organic chemistry has become a valuable tool in the field of bioorthogonal chemistry, offering insights and aiding progression this branch chemistry. In review, I present an overview computational work field, including exploration both primary analysis methods used their application main areas chemistry: (3 + 2) [4 2] cycloadditions. context cycloadditions, detailed studies electronic effects have informed evolution cycloalkyne/1,3-dipole Through techniques, researchers found ways to adjust structure via hyperconjugation enhance reactions without compromising stability. For such as distortion/interaction energy decomposition been beneficial, leading development reactants with improved reactivity creation orthogonal reaction pairs. To conclude, touch upon emerging fields cheminformatics machine learning, which promise play role future discovery optimization.

Language: Английский

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The Cambridge Structural Database and structural dynamics

Structural Dynamics, Journal Year: 2024, Volume and Issue: 11(2)

Published: March 1, 2024

With the availability of computer readable information in Cambridge Structural Database (CSD), wide ranging, largely automated comparisons fragment, molecular, and crystal structures have become possible. They show that distributions interatomic distances, angles, torsion angles for a given structural fragment occurring different environments are highly correlated among themselves with other observables such as spectroscopic signals, reaction activation energies. The correlations often extend continuously over large ranges parameter values. reminiscent bond breaking forming reactions, polyhedral rearrangements, conformational changes. map-qualitatively-the regions space which molecular dynamics take place, namely, low energy respective (free) surfaces. extension continuous nature provides an organizing principle groups data suggests reconsideration traditional definitions descriptions bonds, "nonbonded" "noncovalent" interactions terms Lewis acids interacting bases. These aspects illustrated selected examples historic importance some later developments. It seems amount CSD (and databases) knowledge on of, within, this body should allow one-in near future-to make credible interpolations possibly predictions their properties machine learning methods.

Language: Английский

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Directionality of Halogen‐Bonds: Insights from 2D Energy Decomposition Analysis

Chemistry - An Asian Journal, Journal Year: 2024, Volume and Issue: 19(5)

Published: Feb. 23, 2024

Abstract Halogen bonds are typically observed to have a linear arrangement with 180° angle between the nucleophile and halogen bond acceptor X−R. This linearity is commonly explained using σ‐hole model, although there been alternative explanations involving exchange repulsion forces. We employ two‐dimensional Distortion/Interaction Energy Decomposition Analysis examine archetypal H 3 N⋯X 2 systems. Our results indicate that predominantly electrostatic, their directionality largely due decreased Pauli in configurations as opposed angled ones I Br As we move smaller halogens, Cl F , influence of diminishes, energy surface shaped by orbital interactions electrostatic These support role forces influencing strong bonds. Additionally, demonstrate 2D useful tool for enhancing our understanding nature potential surfaces noncovalent interactions.

Language: Английский

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Biocatalytic and Regioselective Exchange of 2‐O‐Benzoyl for 2‐O‐(m‐Substituted)Benzoyl Groups to Make Precursors of Next‐Generation Paclitaxel Drugs

ChemCatChem, Journal Year: 2024, Volume and Issue: 16(9)

Published: March 11, 2024

Abstract A taxane 2‐ O ‐benzoyltransferase ( m TBT, derived from Accession: AF297618) biocatalyzed the dearoylation and rearoylation of next‐generation precursors drugs effective against multidrug‐resistant cancer cells. Various taxanes bearing an acyl, hydroxyl, or oxo group at C13 were screened to assess their turnover by TBT catalysis. The 13‐oxotaxanes most productive, where ‐debenzoylation 13‐oxobaccatin III was turned over faster compared 13‐oxo‐10‐ ‐( n ‐propanoyl)‐10‐ ‐deacetylbaccatin ‐(cyclopropane carbonyl)‐10‐ III, yielding ~20 mg each. catalysis likely affected intramolecular hydrogen bond with C13−hydroxyl. Oxidation 13‐oxo recovered experimental data for debenzoylation reaction supported Gaussian‐accelerated molecular dynamics simulations that evaluated conformational changes caused different functional groups substrate. These findings also helped postulate ‐benzoylation occurs on paclitaxel pathway in nature. rearoylated debenzoylated acceptors fastest a non‐natural 3‐fluorobenzoyl CoA among other aroyl thioesters evaluated, ~10 each excellent regioselectivity laboratory scale. Reducing hydroxyl yielded key modified baccatin (~10 scale) new‐generation taxoids.

Language: Английский

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Origin of the Felkin–Anh(–Eisenstein) model: a quantitative rationalization of a seminal concept

Chemical Science, Journal Year: 2024, Volume and Issue: 15(31), P. 12380 - 12387

Published: Jan. 1, 2024

The origin of the widely used Felkin–Anh(–Eisentein) model is quantitatively analyzed in detail by means state-of-the-art computational methods.

Language: Английский

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Efficient and Flexible Approach for Local Distortion: Distortion Distribution Analysis enabled by Fragmentation

Chemical Science, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 23, 2024

A general, efficient and flexible approach based on fragmentation ONIOM-type boundary strategies aids computational experimental chemists in visualizing distortion maps evaluating the local energy of various molecules.

Language: Английский

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Nucleophilic addition to carbonyl groups from qualitative to quantitative computational studies. A historical perspective

Comptes Rendus Chimie, Journal Year: 2024, Volume and Issue: 27(S2), P. 5 - 19

Published: March 6, 2024

Nucleophilic addition to carbonyl groups is one of the most important reactions in organic synthesis. In case a prochiral group, preference for nucleophile face π system leads unequal amounts two possible diastereoisomers. The mechanism this reaction various nucleophiles (especially early main group hydride and Grignard reagents) noncyclic cyclic aldehydes or ketones has fascinated computational chemists nearly 40 years. This article describes research that been done on topic, incentive present author being she started her with topic returning it recent L'addition d'un nucléophile sur un composé carbonylé est une des réactions essentielles en synthèse organique. Si le groupe carbonyle prochiral, l'addition les deux faces du système ne sont pas équivalentes et la réaction conduit à excès diastéréoisomères. Le mécanisme de ces pour divers nucléophiles (hydrures éléments principal réactifs type particulier) aldéhydes ou cétones cycliques non attiré l'attention nombreux théoriciens depuis pratiquement ans. Cet décrit l'historique recherches dans ce domaine. L'auteure s'est intéressée sujet car elle entrée recherche avec domaine y revenue toutes dernières années.

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Benzoyl Valine Quasiracemates: Pairing CF₃ Quasienantiomers with H to t-Butyl

Crystal Growth & Design, Journal Year: 2024, Volume and Issue: 24(9), P. 3967 - 3976

Published: April 15, 2024

Understanding the interplay of structural features responsible for molecular assembly is essential crystal engineering. When assembling molecules with encoded motifs, first choice supramolecular strategies almost always include robust directional nonbonded contacts. Quasiracemic materials, considered near racemates since cocrystallization occurs chemically unique components, lack a framework or functional group restrictions, highlighting importance shape to assembly. Recently, our reported quasiracemates derived from benzoyl leucine/phenylalanine derivatives two points chemical difference. In this study, we modified valine and increased scope work by imposing larger variance in side chain substituents. Pairing CF3 component quasienantiomers that differ iteratively hydrogen t-butyl offers an important view into landscape these materials. Single-crystal X-ray crystallography lattice energy assessments, coupled conformational structure similarity searches, show elevated degree isomorphism many targeted 17 quasiracemates. These amino acid architectures create extended hydrogen-bond patterns provide enhanced opportunities study space recognition profiles diverse family quasienantiomeric components.

Language: Английский

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