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Configurations and conformations of some methyl‐substituted 2,4‐dioxabicyclo[3.3.1]nonanes
Author(s) -
Mattinen Jorma,
Pihlaja Kalevi,
Czombos Jószef,
Bartók Mihály
Publication year - 1988
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.1260260618
Subject(s) - chemistry , deuterium , degenerate energy levels , nuclear magnetic resonance spectroscopy , spectral line , nmr spectra database , proton nmr , derivative (finance) , stereochemistry , spectroscopy , computational chemistry , deuterium nmr , atomic physics , physics , quantum mechanics , astronomy , financial economics , economics
Three dimethyl‐ and one trimethyl‐2,4‐dioxabicyclo[3.3.1]nonanes were prepared and their configurations and conformations were determined by means of multinuclear high‐field NMR spectroscopy. Even at 400 MHz the proton spectra were so degenerate that several 2D experiments and, also, deuterium NMR had to be used to make the spectral analysis possible. 13 C and 17 O NMR spectra are also reported. The information obtained shows that two of the dimethyl derivatives are in boat–chair conformations with 3α9 syn and 3α6α configurations, whereas the third dimethyl and the trimethyl derivative exist in chair–chair conformations with 3β9 syn and 3β9 syn 9 anti configurations.