Abstract: Under the CVFF force field and in DMSO, the conformations of α-monosubstituted cyclododecanones were studied by molecular dynamics at room temperature. The results show that the ring skeleton of the preferred conformation is [3333], with the carbonyl group being present in the C2 position, which is consistent with the experimental results. The interconversion between α-corner-syn-[3333]-2-one and α-side-exo-[3333]-2-one was analyzed by using dynamics mimesis method. The calculated results show that their interconversion paths are consistent basically, the preferred conformation is α-side-exo-[3333]-2-one and the interconversion energy barrier is increased along with the increase of the volume augmentation of the substituent groups. For α-chloro- and bromo-cyclododecanones, the maximum barriers are 43.9 and 44.3 kJ/mol, respectively, and the corresponding conformation is α-side-exo-[31233]-2-one. For α-alkylcyclododecanones, the maximum barrier is as high as 53.9 kJ/mol, and the corresponding conformation is α-side-exo-[31233]-2-one. While α-amino- and hydroxy-cyclododecacones, the conformation of the maximum energy is α-side-exo-[31323]-1-one, and α-phenylthio- and benzyl-cyclododecanones, apart from {α-side-}exo-[3333]-2-one conformation, the another stable conformation is α-side-exo-[4233]-3-one instead of α-corner-syn-[3333]-2-one.

Key words: Monosubstituted cyclododecanone, Preferred conformation, Molecular dynamical mimesis