Long Range Phenomena VI [1] CIS‐ and Trans‐Isomers of Ethylheptenoates

Anteunis, M.; Bruyn, André De; Pooter, H. De; Verhegge, G.

doi:10.1002/bscb.19680770702

Cited by 6 publications

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Long Range Phenomena VII [1] Atypical Long Range Paths in 1,3‐Thioxanes and 1,3‐Dithianes

Gelan¹,

Anteunis²

1968

Bulletin des Soc Chimique

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LONG RANGE PHENOMENA V11 [I] ATYPICAL LONG RANGE PATHS IN I,3-THIOXANES A N D 1,3-DITHIANES J . GELAN and M. ANTEUNISAnalogous long range phenomena as observed in 1,3-dioxanes [2-4] are found in 1,3-thioxanes and 1,3-dithianes. Coupling through oxygen is much less than through sulphur in 1,3-thioxanes. This is of great help in structure elucidation of I ,3-thioxane derivatives. The special conformation of this ring can be at the basis of this observation. The easy distortion of the ring of the sulphur analogs of 1,3-dioxanes is illustrated by the fact that the occurrenceof these long range phenomena depends strongly of the degree and nature of substitution. " Classical " (planar zig-zag) " anomalous " paths J2e,4e = 1.0-1.5* J2e,4n = 0.5* J2e,5e = 0.9* J 2~, 5 a = 0 J2o,4e = 0.4 J$n,6a = ON'*) J40,6p = 0.5(5*) J2a,4a = 0.3 448 J. Gelan and M. AnteunisIn contrast, the peaks belonging to H-2e, as a rule, are enlarged, or even multiple (J2 e,4e and/or J, e,5 and/or J, e,4a). As the (nonkxistence of long range phenomena depends in a subtile manner on the geometry of the bond-path followed, it was interesting to look at the 1,3-thioxane (11) and 1,3-dithiane ring (III). It has been found that the switch from 0 to S generally causes an increase of the " atypical " (non-straight zip-zag) coupling constants.

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