Synthesis and Crystal Structure of Novel alpha-Monosubstituted Cyclododecanone Oxime

Three kinds of novel alpha-monosubstituted cyclododecanone mimes were synthesized by the reaction of alpha-monosubstituted cyclododecanone with hydroxylamine. The X-ray diffraction analysis showed that they had different conformations, in which the parent ring took [3333] and [2334] conformation and the substituting group was at alpha-side-exo or alpha-corner-anti position. These results were rationalized by "corner-position carbonyl participation" of raw materials, "memory effect", and hydrogen-bonding between hydroxylamine and alpha-monosubstituted cyclododecanone. In general, an amine molecule approaches cyclododecanone with the bigger groups or intramolecular H-boncling from the side with less hindrance or not breaking hydrogen-bond, resulting in alpha-corner-ant, monosubstituted cyclododecanone mimes, whereas an approach of an amine molecule from the other side with a strong hydrogen bonding network gives rise to alpha-side-exo monosubstituted cyclododecanone (mimes When cyclododecanone with smaller groups or weak intermolecular H-bonding, an amine molecule approaches from both sides to afford alpha-side-exo and alpha-corner-anti monosubstituted cyclododecanone oximes.