Conformational Behavior of cis-2-Methoxy, cis-2-Methylthio, and cis-2-Methylselenocyclohexanol:  A Theoretical and Experimental Investigation

Bocca, Cleverson C.; Basso, Ernani A.; Fiorin, Barbara C.; Tormena, Cláudio F.; Santos, Francisco P. dos

doi:10.1021/jp061502n

Cited by 9 publications

(19 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the last two decades, several studies have been conducted to describe the conformational preferences of several six-membered ring systems, with cyclohexane systems being the most studied. In methylcyclohexane, the methyl group clearly preferentially adopts the equatorial orientation, but the reasons for this preference are still controversial. − For more complex molecular systems, such as 1,2-disubstituted cyclohexanes, − 2-substituted cyclohexanones, − and 2-substituted methylenecyclohexanes, the conformation equilibrium involves axial and equatorial conformers, and the preference for axial or equatorial is dictated by the balance between stereoelectronic interactions present in each molecular system.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Theoretical Studies of Intramolecular Hydrogen Bonding in 3-Hydroxytetrahydropyran: Beyond AIM Analysis

et al. 2014

View full text Add to dashboard Cite

The conformational preferences of 3-hydroxytetrahydropyran (1) were evaluated using infrared and nuclear magnetic resonance spectroscopic data in solvents of different polarities. Theoretical calculations in the isolated phase and including the solvent effect were performed, showing that the most stable conformations for compound 1 are those containing the substituent in the axial and equatorial orientations. The axial conformation is more stable in the isolated phase and in a nonpolar solvent, while the equatorial conformation is more stable than the axial in polar media. The occurrence of intramolecular hydrogen-bonded O-H···O in the axial conformer was detected from infrared spectra in a nonpolar solvent at different concentrations. Our attempt to evaluate this interaction using population natural bond orbital and topological quantum theory of atoms in molecules analyses failed, but topological noncovalent interaction analysis was capable of characterizing it.

show abstract

Section: Introductionmentioning

confidence: 99%

Experimental and Theoretical Studies of Intramolecular Hydrogen Bonding in 3-Hydroxytetrahydropyran: Beyond AIM Analysis

et al. 2014

View full text Add to dashboard Cite

show abstract

“…This new series includes methoxyl, methylthio, and methylseleno groups as counterparts of fluorine, chlorine, and bromine. Several studies describe what happens in the conformational equilibrium with this change in substituents on cyclohexanols, , cyclohexanones, − cyclopentanones, and N,N -dimethylacetamides . These studies are briefly discussed in the Supporting Information (SI, Section A).…”

Section: Introductionmentioning

confidence: 99%

Conformational Isomerism of 3-Chalcogenomethyl-N-Methyl-2-Pyrrolidinones: Insights from NMR Spectroscopy and Molecular Modeling

et al. 2020

View full text Add to dashboard Cite

A conformational analysis of N-methyl-2-pyrrolidinone 3-substituted by methoxyl, thiomethoxyl, and selenomethoxyl is reported by means of 1H nuclear magnetic resonance spectroscopy and electronic structure calculations. The five-membered ring has an envelope conformation with the α-carbonyl substituent being able to assume two positions: pseudo-axial and pseudo-equatorial. In vacuum, the calculations pointed to the pseudo-axial conformer as the most stable one, and this preference increases with the size of the substituent and a decrease in its electronegativity. Natural bond orbital analysis evidenced the importance of electron delocalization on the stability, and a principal component of analysis (PCA) plot of the hyperconjugative interactions revealed the main ones. Steric and electrostatic effects were also investigated by energy decomposition analysis.

show abstract

“…Although there have been several works on the conformational preference of 1,2-disubstituted cyclohexanes [4,11–14 20,22–29], cis -2-halocyclohexylamines have not yet been consistently studied. This is quite surprising, due to the possibilities of effects that add up or compete with each other in the presence of these two groups.…”

Section: Introductionmentioning

confidence: 99%

Strong hyperconjugative interactions limit solvent and substituent influence on conformational equilibrium: the case of cis-2-halocyclohexylamines

Francisco¹,

Fernandes²,

Melo³

et al. 2019

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

The presence of strong stereoelectronic interactions involving the substituents in cis-2-substituted cyclohexanes may lead to results different from those expected. In this work, we studied the conformational behavior of cis-2-fluoro- (F), cis-2-chloro- (Cl), cis-2-bromo- (Br) and cis-2-iodocyclohexylamine (I) by dynamic NMR and theoretical calculations. The experimental data pointed to an equilibrium strongly shifted toward the ea conformer (equatorial amine group and axial halogen), with populations greater than 90% for F, Cl and Br in both dichloromethane-d 2 and methanol-d 4. Theoretical calculations (M06-2X/6-311++G(2df,2p)) were in agreement with the experimental, with no influence of the solvent or the halogen on the equilibrium. A principal component analysis of natural bond orbital energies pointed to the σ*C–X and σC–H orbitals and the halogen lone pairs (LPX) as the most significant for the hyperconjugative interactions that influenced the equilibrium. The σC–H → σ*C–X hyperconjugation and the interactions involving the LPX counterbalance each other, explaining the non-influence of the halogen on the conformational equilibrium. These interactions are responsible for the strong preference for the ea conformer in cis-2-halocyclohexylamines, being strong enough to restrain the shift in the equilibrium due to other factors such as steric repulsion or solvent effects.

show abstract

Conformational Behavior of cis-2-Methoxy, cis-2-Methylthio, and cis-2-Methylselenocyclohexanol: A Theoretical and Experimental Investigation

Cited by 9 publications

References 14 publications

Experimental and Theoretical Studies of Intramolecular Hydrogen Bonding in 3-Hydroxytetrahydropyran: Beyond AIM Analysis

Experimental and Theoretical Studies of Intramolecular Hydrogen Bonding in 3-Hydroxytetrahydropyran: Beyond AIM Analysis

Conformational Isomerism of 3-Chalcogenomethyl-N-Methyl-2-Pyrrolidinones: Insights from NMR Spectroscopy and Molecular Modeling

Strong hyperconjugative interactions limit solvent and substituent influence on conformational equilibrium: the case of cis-2-halocyclohexylamines

Contact Info

Product

Resources

About