A5010559157- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Fluorine in Organic Chemistry
- Molecular Spectroscopy and Structure
- Crystallography and molecular interactions
- Oxidative Organic Chemistry Reactions
- Inorganic Fluorides and Related Compounds
- Organic Chemistry Cycloaddition Reactions
- Asymmetric Synthesis and Catalysis
- Supramolecular Chemistry and Complexes
- Synthesis of Indole Derivatives
- Chemical Synthesis and Analysis
- Carbohydrate Chemistry and Synthesis
- Click Chemistry and Applications
- Various Chemistry Research Topics
- Molecular spectroscopy and chirality
- Synthesis and Reactions of Organic Compounds
- Advanced Chemical Physics Studies
- Photochemistry and Electron Transfer Studies
- Synthetic Organic Chemistry Methods
Universidade Estadual de Campinas (UNICAMP)
2019-2025
Pontifícia Universidade Católica de Campinas
2021
Despite the remarkable advancements in hypervalent iodine chemistry, exploration of bromine and chlorine analogues remains its infancy due to their difficult synthesis. Herein, we introduce six-membered cyclic λ3-bromanes λ3-chloranes. Through single-crystal X-ray structural analyses conformational studies, delineate crucial bonding patterns pivotal for thermodynamic stability these compounds. Notably, investigations reveal pronounced π-π stacking phenomena within crystal lattice...
Despite the remarkable advancements in hypervalent iodine chemistry, exploration of bromine and chlorine analogues remains its infancy due to their difficult synthesis. Herein, we introduce six‐membered cyclic λ3‐bromanes λ3‐chloranes. Through single‐crystal X‐ray structural analyses conformational studies, delineate crucial bonding patterns pivotal for thermodynamic stability these compounds. Notably, investigations reveal pronounced π‐π stacking phenomena within crystal lattice...
The conformational equilibria of selectively halogenated cyclohexanes are explored both experimentally (VT-NMR) for 1,1,4,-trifluorocyclohexane 7 and by computational analysis (M06-2X/aug-cc-pVTZ level), with the latter approach extending to a wider range more highly fluorinated cyclohexanes. Perhaps unexpectedly, 7ax is preferred over 7eq conformation ΔG = 1.06 kcal mol–1, contradicting accepted norm substituents on axial preference stronger again in 1,1,3,3,4,5,5,-heptafluorocyclohexane 9...
Theory and Langmuir isotherm analysis was used to explore the conformations molecular packing of alkyl all-<italic>cis</italic> 2,3,4,5,6-pentafluorocyclohexyl motifs, which are prepared by direct aryl hydrogenations from alkyl- or vinyl-pentafluoroaryl benzenes.
Abstract We report counter‐intuitive axial preferences in non‐stereochemically biased, selectively fluorinated methoxycyclohexanes. These pseudo‐anomeric effects are apparent when electronegative CF 2 groups placed at the C‐2, C‐4 and C‐6 positions of cyclohexane ring to render C‐3/5 hydrogen atoms electropositive. The electrostatic interaction between these ‐OMe oxygen is stabilising. effect explored using high‐level ab initio DFT calculations framework NBO, QTAIM NCI analysis across a...
Concise and general synthesis protocols are reported to generate all-syn mono-, di- tri-alkylated cyclohexanes where a single fluorine is located on the remaining carbons of ring. The alkyl groups positioned lie equatorially have triaxial C-F bonds imparting polarity these ring systems. Intermolecular electrostatic interactions in solid-state structure trialkylated systems explored resultant supramolecular order opens up prospects for design soft materials.
In this theory study the dominance of non-classical 1,3-diaxial CH<sub>ax</sub>⋯OC hydrogen bonds (NCHBs) dictating anomeric effects in fluorinated methoxycyclohexanes and 2-methoxytetrahydropyrans is demonstrated, a phenomenon which most often described as consequence hyperconjugation.
The (β,β',β″-trifluoro)-tert-butyl (TFTB) group has received very little attention in the literature. This work presents a direct synthesis of this and explores its properties. TFTB arises when methyl groups tert-butyl moiety are exchanged for fluoromethyl groups. Sequential fluoromethylations result decrease Log P (increasing hydrophilicity), ultimately by 1.7 units relative to that benzene itself. A focus is placed on synthetic transformations, conformational analysis, metabolism context...
Theoretical decomposition of "through space" spin-spin coupling constants (SSCCs) in organofluorine compounds signal that intramolecular hydrogen bonds (H-bonds) are not the primary mechanism transmission for SSCCs. Increasing solvent polarity may disrupt H-bonds, but necessarily JFH SSCC. Substituent effects drastically alter SSCC pathway. Accurate analysis requires benchmarking theoretical calculations to support experimental data interpretation.
Theory and solution NMR indicate that all-syn 1,3,5-trifluorocyclohexane 5 adopts the expected tri-equatorial conformation, however in solid state more polar triaxial conformation is observed. This favoured conformations of substituted (Me, OMe, NH(CO)Me, NHBoc) derivatives are investigated to explore C-F preferences.
The importance of electrostatic nonconventional hydrogen bonds (NCHBs) to the pseudo-anomeric effect 4-substituted methoxycyclohexanes is evaluated using theory [natural bond orbital (NBO)] deconvolute from other contributing effects. There an interesting interplay between σCH → σCX* hyperconjugation and electropositive charge on 3,5-axial hydrogens (Hax). In essence, better (or πCO*) acceptors increase 3,5-CHax, which in turn strengthens Cδ+Hax···δ-OMe NCHB interactions.
A route is developed to (γ,γ',γ'''-trifluoro)neopentyl (TFNP) aryl ethers extend the methods for introduction of tert-butyl group, carrying a fluorine on each methyl substituents. The combines neopentyltosylate 3 with phenols and thiophenols give efficient substitution reactions corresponding TFNP ethers. three C-F bonds adopt helical propeller conformation as revealed by computation single crystal X-ray structure analysis. LogPs are lower (more hydrophilic) than their neopentyl analogues....
Nucleophilic aromatic substitutions (SNAr) of alkoxides on pentafluoroaryl ethers are explored as a first step in synthesis sequence to generate all-cis 2,3,5,6-tetrafluorocyclohexyl-1,4-dialkyl 1. The SNAr reaction was both experimentally and theoretically rationalize ortho/para/meta selectivities. tert-Butyl deprotection products followed by phenol alkylations introduces versatility the synthesis. final Rh(CAAC) 3 catalyzed aryl hydrogenation intermediate tetrafluoroaryl-1,4-diethers...
The knowledge about the effects that rule internal rotation of methyl groups is key in understanding physical chemistry properties and reactivity molecules. Using this as motivation, different substituted acetyl were studied with NBO theory govern conformational preferences calculated by computational methods.
The importance of electrostatic non-conventional hydrogen bonds (NCHBs) to the pseudo-anomeric effect 4-substituted methoxycyclohexanes is evaluated using theory (NBO) deconvolute from other contributing effects. There an interesting interplay between σCH → σ*CX hyperconjugation and electropositive charge on 3,5-axial hydrogens (Hax). In essence better (or 𝜋*CO) acceptors increase 3,5-CHax, which in turn strengthens Cδ⁺Hax···δ⁻OMe NCHB interactions.