Synthesis and carbon-13 nuclear magnetic resonance spectroscopy of 5,6-dihydro-2-methyl-1,4-oxathiin, trans-tetrahydro-1,4-benzoxathiin, 1,4-tetrahydro-[9,10]benzoxathiin, the 4-oxides, 4,4-dioxides and related acyclic compounds

✍ Scribed by Robert P. Rooney; John C. Dyer; Slayton A. Evans Jr

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: English
• Weight: 674 KB
• Volume: 16
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1270160404

✦ Synopsis

Abstract

The results of a ^13^C NMR spectral investigation involving 5,6‐dihydro‐1,4‐oxathiins, 1,4‐tetrahydro[9,10]benzoxathiin, trans‐tetrahydro‐1,4‐benzoxathiin, and the corresponding sulfoxides and sulfones are reported. An interpretation involving a dipolar structure with (2__p__→2__p__)π conjugation as opposed to (2__p__→3__d__)π interactions with the vinyloxy sulfides seems consistent with trends in the ^13^C NMR shifts. For the sulfoxides and sulfones, the substitutent‐induced chemical shift (SCS) effects at the β vinylic carbons (βSO and βSO~2~ effects) are considerably less than those at sp^3^ carbons. The γSO and γSO~2~ values at the sp^2^γ carbons indicate deshielding, in contrast to the shielding at the sp^3^ carbons.