NMR Experiments on Acetalsl XXVI. Influence of β-Substitution on Geminal Coupling Values in 1,3-Dioxanes

✍ Scribed by G. Swaelens; M. Anteunis; D. Tavernier

• Publisher: Wiley (John Wiley & Sons)
• Year: 2010
• Weight: 482 KB
• Volume: 79
• Category: Article
• ISSN: 0037-9646
• DOI: 10.1002/bscb.19700790706

✦ Synopsis

Abstract

The influences of β‐substituents–either in equatorial or in axial positions–on the numerical value of ^2^J(H‐2) (the geminal coupling J(OCH~2~O)) in 1,3‐dioxanes, have been scrutinized. Influences on ^2^J(H‐2) by the nature and electronegativity of the substituents seem to depend on the orientation of these substituents. Equatorial substituents cause composite influences, alkyl groups leading to an almost independent constant value for ^2^J(H‐2) = −6.2 cps.

Suitable equatorial ρ‐substituted phenyl derivatives show a numerical decrease with increasing electrodonating capacity (range 6.2‐6.5 cps) however. The same, but more pronounced trend is found for the axial substituents.