Dihedral angle and bond angle dependence of vicinal proton-fluorine spin-spin coupling

Williamson, Kenneth L.; Hsu, Yuan‐Fang Li; Hall, Frances; Swager, Susan; Coulter, Margaret S.

doi:10.1021/ja01026a028

Cited by 74 publications

(27 citation statements)

References 2 publications

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“…When diphenyl was employed as the substrate, the reaction stopped at the monofluoroalkylsulfinylation stage, giving para-substituted 1h and 1i as the only product (entries 8 and 9, Table 2). However, no sulfinylated product was observed in the case of terphenyl (entry 10, Table 2), as confirmed by 19 …”

Section: Resultssupporting

confidence: 57%

“…It was found that when sodium 2-chloro-1,1,2,2-tetrafluoroethanesulfinate reacted with benzene and triflic anhydride in triflic acid at room temperature, the system became ineffectual. 19 F NMR analyses of the reaction mixture showed the formation of undesired polyarylenesulfonium salts [15][16][17]. The yield of 1-(2-chloro-1,1,2,2-tetrafluoroethylsulfinyl)benzene (1d) was only 20% after 23 h, although the polyfluoroalkylsulfinate salt was completely consumed (entry 1, Table 1).…”

Section: Resultsmentioning

confidence: 99%

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One-pot synthesis of arylfluoroalkylsulfoxides and study of their anomalous 19F NMR behavior

Zhang

Wang

Chen

et al. 2010

Journal of Fluorine Chemistry

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Section: Resultssupporting

confidence: 57%

Section: Resultsmentioning

confidence: 99%

One-pot synthesis of arylfluoroalkylsulfoxides and study of their anomalous 19F NMR behavior

Zhang

Wang

Chen

et al. 2010

Journal of Fluorine Chemistry

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“…The fluorine resonance at −100.79 ppm is hence assigned preliminary to Fα and the resonance at −113.57 ppm to Fβ. The dependence of 3 J FH upon molecular parameters is similar to 3 J HH , following a Karplus-like dependence [18,45,46] , but the range of 3 J FH values varies from ≈50 Hz for θ FH ≈ 180…”

Section: Assignment Of Diastereotopic Fluorine Atomsmentioning

confidence: 84%

Application of fluorine NMR for structure identification of steroids

Ampt

Aspers

Jaeger

et al. 2011

Magnetic Reson in Chemistry

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Fluorinated steroids were examined using 1D and 2D homo- and heteronuclear (19)F NMR, such as (19)F-(1) H and (19)F-(13)C. The utilization of fluorine NMR accounted for spectral simplification and resulted in a straightforward pathway for the determination of structures including the configuration of these compounds; these steroids present an illustrative example for other types of fluorinated compounds, which are increasingly encountered in drug discovery. The potential of (19)F NMR is elaborated on in detail for two compounds containing diastereotopic fluorines with different coupling patterns. The analysis of the coupling patterns and the through-space interactions resulted in the determination of the structure and configuration. Heteronuclear correlation experiments, i.e. (19)F-(1)H HETCOR, (19)F-(13)C HMQC and HMBC, and (19)F-(1)H HOESY, were applied to determine first the relative stereochemistry and then the molecular configuration at C4 and C5 of a steroidal compound bearing a fused three-membered ring with two fluorine substituents. These examples proved (19)F NMR to be a useful addition to the extensively used (1)H and (13)C NMR within structure elucidation and configuration determination of small molecules.

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“…If it is assumed that (i) the inherent temperature dependence of the vicinal 'H-'H coupling constants is negligible (13), (ii) conformers K and L have the same dihedral angles, and (iii) simple Karplus relationships (15,16) apply to both K and L, i.e. they have the same Karplus coefficients, we can derive an estimate of the enthalpy difference between K and L as follows.…”

Section: Complexes Of (Ch) Aschfchfas (Ch) mentioning

confidence: 99%

“…If + is the dihedral angle and 0 the in-plane projection of the "tetrahedral" angles (assumed to be 120" (15,17)) about the ring carbon atoms as in M, we can derive expressions for the vicinal 'H-'H coupling constants of the individual conformers K and L.…”

Section: Complexes Of (Ch) Aschfchfas (Ch) mentioning

confidence: 99%

Variable Temperature Nuclear Magnetic Resonance Studies of Some Five-Membered Ring Chelate Complexes

Cullen¹,

Hall²,

Ward³

1975

Can. J. Chem.

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The temperature dependence of the n.m.r. spectra of nine ditertiary arsine chelate complexes of formula (CH3)2AsC(3)(3′)C(4) (4′)As(CH3)2M(CO)3X has been studied (M = Mo, Cr; X = CO; M = Mn; X = halogen; (3), (3′), (4), (4′) = H, F, Si(CH3)3, CN; but not all combinations ). Significant variation in coupling constants, indicating a shift in the conformer populations, was found only for the CHFCF2 bridged Mn(CO)3Cl complex, the CH2CF2 bridged Mn(CO)3Cl complex, and the CHFCHF bridged Mo(CO)4 complex. In the last case the 3JHH coupling constants were used to estimate ΔH ∼ 1 kcal/mol and ΔS ∼ 3 e.u for the conformational equilibrium.

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Dihedral angle and bond angle dependence of vicinal proton-fluorine spin-spin coupling

Cited by 74 publications

References 2 publications

One-pot synthesis of arylfluoroalkylsulfoxides and study of their anomalous 19F NMR behavior

One-pot synthesis of arylfluoroalkylsulfoxides and study of their anomalous 19F NMR behavior

Application of fluorine NMR for structure identification of steroids

Variable Temperature Nuclear Magnetic Resonance Studies of Some Five-Membered Ring Chelate Complexes

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