TY - JOUR A1 - Wang, Yi A1 - Kirsch, Peer A1 - Lebl, Tomas A1 - Slawin, Alexandra M. Z. A1 - O'Hagan, David T1 - The preferred conformation of erythro- and threo-1,2-difluorocyclododecanes JF - Beilstein Journal of Organic Chemistry PY - 2012/// VL - 8 SP - 1271 EP - 1278 SN - 1860-5397 DO - 10.3762/bjoc.8.143 PB - Beilstein-Institut JA - Beilstein J. Org. Chem. UR - https://doi.org/10.3762/bjoc.8.143 KW - alicyclic chemistry KW - conformational analysis KW - cyclododecane KW - 19F NMR KW - organo-fluorine chemistry KW - transannular interactions N2 - 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 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–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. ER - TY - JOUR AU - Dunitz, J. D. AU - Shearer, H. M. M. JF - Helv. Chim. Acta PY - 1960/// VL - 43 SP - 18 EP - 35 DO - 10.1002/hlca.19600430104 ER - TY - JOUR AU - Bürgi, H.-B. AU - Dunitz, J. D. JF - Helv. Chim. Acta PY - 1993/// VL - 76 SP - 1115 EP - 1166 DO - 10.1002/hlca.19930760303 ER - TY - JOUR AU - Dale, J. JF - Acta Chem. Scand. PY - 1973/// VL - 27 SP - 1115 EP - 1129 DO - 10.3891/acta.chem.scand.27-1115 ER - TY - BOOK AU - Eliel, E. L. AU - Wilen, S. H. T1 - Stereochemistry of Organic Compounds PY - 1994/// PB - Wiley-Interscience CY - New York ER - TY - JOUR AU - Anet, F. A. L. AU - Rawdah, T. N. JF - J. Am. Chem. Soc. PY - 1978/// VL - 100 SP - 7166 EP - 7171 DO - 10.1021/ja00491a007 ER - TY - JOUR AU - Atavin, E. G. AU - Mastryukov, V. S. AU - Allinger, N. L. AU - Almenningen, A. AU - Seip, R. JF - J. Mol. Struct. PY - 1989/// VL - 212 SP - 87 EP - 95 DO - 10.1016/0022-2860(89)85069-0 ER - TY - JOUR AU - Skibinski, M. AU - Wang, Y. AU - Slawin, A. M. Z. AU - Lebl, T. AU - Kirsch, P. AU - O’Hagan, D. JF - Angew. Chem., Int. Ed. PY - 2011/// VL - 50 SP - 10581 EP - 10584 DO - 10.1002/anie.201105060 ER - TY - JOUR AU - Dasaradhi, L. AU - O'Hagan, D. AU - Petty, M. C. AU - Pearson, C. JF - J. Chem. Soc., Perkin Trans. 2 PY - 1995/// SP - 221 EP - 225 DO - 10.1039/p29950000221 ER - TY - JOUR AU - O'Hagan, D. JF - Chem. Soc. Rev. PY - 2008/// VL - 37 SP - 308 EP - 319 DO - 10.1039/b711844a ER - TY - JOUR AU - Goodman, L. AU - Gu, H. AU - Pophristic, V. JF - J. Phys. Chem. A PY - 2005/// VL - 109 SP - 1223 EP - 1229 DO - 10.1021/jp046290d ER - TY - JOUR AU - Souza, F. R. AU - Freitas, M. P. AU - Rittner, R. JF - J. Mol. Struct. PY - 2008/// VL - 863 SP - 137 EP - 140 DO - 10.1016/j.theochem.2008.06.003 ER - TY - JOUR AU - Michel, D. AU - Schlosser, M. JF - Tetrahedron PY - 2000/// VL - 56 SP - 4253 EP - 4260 DO - 10.1016/S0040-4020(00)00351-3 ER - TY - JOUR AU - Nicoletti, M. AU - O'Hagan, D. AU - Slawin, A. M. Z. JF - J. Am. Chem. Soc. PY - 2005/// VL - 127 SP - 482 EP - 483 DO - 10.1021/ja045299q ER - TY - JOUR AU - Durie, A. J. AU - Slawin, A. M. Z. AU - Lebl, T. AU - Kirsch, P. AU - O'Hagan, D. JF - Chem. Commun. PY - 2011/// VL - 47 SP - 8265 EP - 8267 DO - 10.1039/c1cc13016a ER - TY - JOUR AU - Eyring, H. JF - J. Chem. Phys. PY - 1935/// VL - 3 SP - 107 EP - 115 DO - 10.1063/1.1749604 ER - TY - GEN N1 - Gaussian 03, Revision D.01: M. J. Frisch et al. [see Supporting Information], Gaussian, Inc., Wallingford CT, 2004. The minimum geometries were optimised at the B3LYP/6-311+G(2d,p) level of theory, and were verified to have only positive eigenfrequencies. The energies of the conformers were calculated at the MP2/6-311+G(2d,p) level of theory, by using both B3LYP/6-311+G(2d,p) and M06-2X/6-311+G(2d,p) geometries and zero-point energies. There are slight energy differences but no qualitative changes in the relative energies. ER -