Sulphur-33 nuclear magnetic resonance spectroscopy of sulphones

Hoyle, Jeff; Grossert, J. Stuart; Hooper, D. L.; Sotheeswaran, Subramaniam

doi:10.1139/v86-261

Cited by 7 publications

(3 citation statements)

References 12 publications

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“…Volatiles were removed under reduced pressure, and the crude material was purified by column chromatography (60 mL silica gel, 3:1 hexane/EtOAc) to yield pure sulfone 14 (3.84 g, 22.6 mmol, 88% yield, colorless solid). 1 H NMR analysis is consistent with previously reported data …”

Section: Methodssupporting

confidence: 92%

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Long-Range Reactivity Modulations in Geranyl Chloride Derivatives

Reardon

Tan

et al. 2016

J. Org. Chem.

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Derivatives of geraniol are versatile synthetic intermediates that are useful for synthesizing a variety of terpenoid natural products; however, the results presented herein show that subtle differences in the structures of functionalized geranyl chlorides can significantly impact their abilities to function as effective electrophiles in synthetic reactions. A series of focused kinetics experiments identify specific structure-activity relationships that illustrate the importance not only of steric bulk, but also of electronic effects from distant regions of the molecules that contribute to their overall levels of reactivity. Computational modeling suggests that destabilization of the reactant by filled-filled orbital mixing events in some, but not all, conformations may be a critical contributor to these important electronic effects.

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Section: Methodssupporting

confidence: 92%

“…1 H NMR analysis is consistent with previously reported data. 32 1 H NMR (CDCl 3 , 200 MHz) δ 7.91 (d, J = 7.6 Hz, 2H, Ar), 7.74− 7.47 (m, 3H, Ar), 3.12 (q, J = 7.6 Hz, 2H, CH 2 ), 1.27 (t, J = 7.7 Hz, 3H, CH 3 ).…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Long-Range Reactivity Modulations in Geranyl Chloride Derivatives

Reardon

Tan

et al. 2016

J. Org. Chem.

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“…Although LW depends on 2 , we are not able to determine the sign of , but the existence of correlation in Eqn (10) seems to suggest that it could be positive. Moreover, both experimental j j and theoretical DFT decrease with the increasing electron-withdrawing ability of X substituents.…”

Section: S Linewidths and Nuclear Quadrupole Coupling Constantsmentioning

confidence: 56%

³³S NMR spectroscopy 3. substituent effects on ³³S NMR parameters in 2‐substituted ethanesulfonates

Musio¹,

Sciacovelli²

2006

Magnetic Reson in Chemistry

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33S NMR parameters (chemical shifts and linewidths) in 2-substituted sodium ethanesulfonates, XCH2CH2SO3Na (X = H, CH3, OH, SH, NH2, Cl, Br, NH3+) depend upon the electronic properties of substituents. To explain experimental results and obtain additional information on the origin of the observed substituent effect (SE), sulfur isotropic absolute shielding constants have been calculated at DFT level of theory (B3LYP/6-311++G(2d,p)) by gauge-including atomic orbitals (GIAO) method. Data have been interpreted with the aid of natural bond orbital (NBO) method and natural chemical shielding (NCS) analysis. It has been demonstrated that in the class of compounds considered the diamagnetic contribution to sulfur-shielding constant is constant and the observed upfield shift of 33S resonance induced by electron-withdrawing substituents (reverse chemical shift effect) can be related to variations of the paramagnetic contribution. Substituents with different electronic properties cause variations in the polarization of S-C and S-O bonds of the -C-SO3- moiety thus determining changes of the electron density at sulfur nucleus and consequently the expansion or contraction of 3p sulfur orbitals. Also oxygen lone-pairs and sulfur core 2p electrons can play an active role in determining the paramagnetic contribution to sulfur shielding. With regard to linewidth variations, they can be ascribed primarily to changes in the nuclear quadrupole coupling constant values. B3LYP/6-311++G(2d,p) method allows obtaining a good reproducibility of SE on the electric field gradient (EFG) at sulfur, although its values tend to be underestimated significantly. Moreover, 17O shielding constants have been calculated.

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