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1 H, 13 C and 17 O NMR spectroscopic study of four bicyclo [3.1.1]heptenes (derivatives of α‐pinene) and four bicyclo[3.1.1]heptanes (derivatives of β‐pinene)
Author(s) -
Laihia Katri,
Kolehmainen Erkki,
Malkavaara Petteri,
Korvola Jorma,
Mänttäri Pia,
Kauppinen Reijo
Publication year - 1992
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260300811
Subject(s) - chemistry , bicyclic molecule , heptane , nmr spectra database , methylene , carbon 13 nmr , spectral line , steric effects , chemical shift , stereochemistry , ring (chemistry) , ring strain , proton nmr , medicinal chemistry , organic chemistry , astronomy , physics
Abstract Four derivatives of 2, 6, 6‐trimethylbicyclo[3.1.1]hept‐2‐ene (α‐pinene) and four derivatives of 2‐methylene‐6, 6‐dimethylbicyclo[3.1.1]heptane (β‐pinene) were synthesized and their 1 H, 13 C and 17 O NMR spectra were measured, analysed and assigned. The 1 H NMR spectral parameters were obtained by computer‐aided analyses of the very complex multi‐spin, second‐order spectra. Some of the 13 C NMR chemical shift assignments of these compounds reported in the literature should be changed, based on these accurate 1 H NMR spectral analyses and carbon‐proton chemical shift correlated spectra (COSY). The new assignments are supported by the 1 J (C, H) values, which show a strong dependence on the bond angle and the steric strain of the ring system concerned.