6533b825fe1ef96bd1281d4e

RESEARCH PRODUCT

Configurational effects in17O NMR chemical shifts of hydroxyl-substituted, bicyclo [2.2.1]heptenes and -heptanes, their methylated derivatives and some related compounds

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Well resolved natural abundance 17O NMR spectra of 27 mono-, di-, tri- and tetrahydroxybicyclo[2.2.1]heptenes and -heptanes (norbornenes or norbornanes), their methylated derivatives and some related compounds were measured for 0.5 M or saturated solutions in acetonitrile at 65°C. In addition, the 17O NMR chemical shifts of 14 aliphatic and alicyclic alcohols were also determined for reference purposes. The 17O NMR chemical shifts of all compounds were assigned. Both methyl- and hydroxyl-induced deshielding β-effects were consistent with those reported in the literature. Similarly, observed shielding γ-effects were in agreement with the earlier observations and characteristic especially for mutual γ-gauche and -eclipsed orientations of substituents. In addition, clear shielding δ-effects (up to 10 ppm) were observed in tri- or tetrahydroxynorbornanes. These δ-effects can be related to the attractive van der Waals interactions observed earlier in 13C NMR chemical shifts.