Oxygen-17 nuclear magnetic resonance spectroscopy of sulfoxides and sulfones. Alkyl substituent-induced chemical-shift effects

Abstract

Oxygen-17 NMR chemical shifts have been determined for a number of cyclic and acyclic as well as aliphatic, olefinic, and aryl sulfoxides and sulfones. The 170 NMR chemical shifts for the acyclic, aliphatic, and aromatic sulfoxides reported here absorb in the narrow range between -20 and +20, while the cyclic, aliphatic sulfoxides absorb between -13 and +66 relative to external (but naturally abundant) H2170. The sulfonyl oxygens are deshielded relative to the sulfinyl oxygens, exhibiting chemical shifts for acyclic and cyclic sulfonyl oxygens between 120 and 183 for the sulfones reported here. Diastereotopic sulfonyl oxygens exhibit chemical shift nonequivalence. Substituent-induced chemical shift effects by a methyl or methylene group on the sulfinyl and sulfonyl oxygens are discussed.

Structure and Dynamics of Polysulfide Clusters in a Nonaqueous Solvent Mixture of 1,3-Dioxolane and 1,2-Dimethoxyethane

“…The geometry optimization and 17 O magnetic shielding calculations of DMSO molecules were performed with the same basis sets and density functional used for the solvated Li x S y clusters. DMSO is a secondary 17 O reference, and the resulting chemical shifts from the calculated values were adjusted to the primary reference of liquid water by adding the neat DMSO's experimental chemical shift with respect to the liquid water reference (+12 ppm 51 ) to the calculated chemical shift with respect to that of DMSO.…”

Oxygen-17 NMR spectroscopy: Basic principles and applications (Part I)

“…Calculated for the most stable of the ''open" forms and the intramolecularly hydrogen-bonded form.A comparison of the diastereomeric sulfoxides of trans-1-thiadecalin of Scheme 31 demonstrates the importance of c-gauche methyl or methylene shielding effects on sulfinyl oxygens in a six-membered ring. The17 O chemical shift of the axial sulfinyl oxygen in I, is more shielded by À17.0 ppm than the equatorial sulfinyl oxygen in II[527,536,537].The17 O chemical shifts of the sulfonyl (-SO 2 -) group in acyclic compounds appear between…”

Acidic and Basic Hydrolysis of an Optically Pure Spiro-λ4-sulfurane: Completely Opposite Stereochemical Outcome

“…On the other hand, the sulfoxides ( 4- 17 O and 5- 17 O ) obtained by hydrolysis of 3a with H 2 17 O (20.3 atom % 17 O) under basic or acidic conditions showed signals with chemical shift of −9.2 and −8.1 ppm in their 17 O NMR spectra, respectively. The values of the chemical shift strongly indicate that under both conditions the oxygen atoms from H 2 17 O were bound to the sulfur atoms …”