%0 Journal Article
%T The preferred conformation of erythro- and threo-1,2-difluorocyclododecanes
%A Yi Wang
%A Peer Kirsch
%A Tomas Lebl
%A Alexandra M. Z. Slawin
%J Beilstein Journal of Organic Chemistry
%D 2012
%I 
%R 10.3762/bjoc.8.143
%X 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每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 19F{1H} 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每F bonds are located corner/edge, rather than edge/edge. These structures avoid placing a C每F bond endo into the ring, and appear to benefit from C每CHF每C angle widening, which relaxes 1,4-H,H transannular interactions.
%K alicyclic chemistry
%K conformational analysis
%K cyclododecane
%K 19F NMR
%K organo-fluorine chemistry
%K transannular interactions
%U http://dx.doi.org/10.3762/bjoc.8.143