The conformations of α-monosubstituted cyclododecanones have been studied by means of molecular dynamics computations, single crystal X- ray analysis and ~1H NMR. Results show that the ring skeleton of their preferred conformation is still [3333], with the carbonyl group present in the 2-C position. The preferred conformation in the crystal is α-corner-syn-substituted conformation. These molecules may adopt two different conformations in solution, the predominant α-side-exo- substituted and α-corner-syn-substituted conformation, which exist in a dynamic equilibrium.

Key words: cyclododecanones, CONFORMATION, MOLECULAR MECHANICS, XRD, 1HNMR