The preferred conformation of erythro- and threo-1,2-difluorocyclododecanes
Abstract
Cyclododecane adopts a square-like structure with corner and edge CH2 groups. In this study erythro- and threo-1,2-difluorocyclododecanes were prepared to explore whether the two vicinal C-F bonds, with different relative configurations, preferably locate at corner/edge or edge/edge locations. Conformational analysis comparing the diastereoisomers was explored by using a combination of F-19{H-1} NMR spectroscopy, computational studies and, in the case of the threo isomer, X-ray structural analysis. In the lowest energy conformers for both diastereoisomers the vicinal C-F bonds are located corner/edge, rather than edge/edge. These structures avoid placing a C-F bond endo into the ring, and appear to benefit from C-CHF-C angle widening, which relaxes 1,4-H, H transannular interactions.
Citation
Wang , Y , Kirsch , P , Lebl , T , Slawin , A M Z & O'Hagan , D 2012 , ' The preferred conformation of erythro- and threo-1,2-difluorocyclododecanes ' , Beilstein Journal of Organic Chemistry , vol. 8 , pp. 1271-1278 . https://doi.org/10.3762/bjoc.8.143
Publication
Beilstein Journal of Organic Chemistry
Status
Peer reviewed
ISSN
1860-5397Type
Journal article
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