Conformation of α,α,α'-Trisubstituted Cyclododecanone

• 来源期刊: 中国化学（英文版）
• 年，卷（期）: 2007,（8）
• 页码范围: 1196-1201
• 页数: 6页
• 语种: 英文

摘要

Ten α,α,α'-trisubstituted cyclododecanones were synthesized and characterized by elemental analyses, infrared,1H NMR and 13C NMR spectra, and X-ray diffraction. NMR data could not give conformational information clearly,but some of their ring skeleton conformations of cyclododecanone moiety were showed to remain the unchanged [3333]-2-one conformation with little distortion, while the others were changed to the [3324]-2-one conformation in their crystal structures. These are consistent with the results of molecular mechanics calculation with Sybyl 6.9 software and Tripos force field, and semi-empirical quantum calculation with AM1 method in Gaussian 98 software.Two geminal substituting groups are located at α-comer carbon atom, and the third group is at α-side-exo carbon atom in both conformations. Both [3333]-2-one and [3324]-2-one conformations are present in a dynamic equilibrium in the solution, but only one preferred conformation exists in the crystal solid.