Lanthanide shift reagents have been used for the conformational analysis of bicyclo[3.3.1]nonan-g-one. Comparison of predicted shifts and experimental values obtained with Eu(fod)3 indicate that the boat-chair conformation constitutes 22% of the mixture of conformers. Bicyclo[3.3.l]nonane (1) and its derivatives have been of considerable interest to organic chemists for many years, l-3 The nonbonded interactions which are anticipated for the dichair conformation (,.$) have generated a high degree of interest in these compounds as possible examples of cyclohexanes with nonchair conformations (R and a). Moreover, the potential for interaction between substituents on the two cyclohexane rings has permitted bicyclo[3.3.l]nonane derivatives to play valuable roles as substrates for mechanistic studies 4-6 and as synthetic intermediates.7-10 The parent compound l has been clearly shown 11 to exist in the dichair conformation, although the interaction between substituents at the 3 and 7 positions can shift the conformational equilibrium such that the chair-boat ($b) predominates. 12 These conclusions from experimental observations are fully supported by a variety of empirical force field (EFF) calcula, tions 13-16 . In this communication we report tive which exists to a substantial extent in stabilizing the dichair conformation, but as an example of a simple bicyclo[3.3.l]nonane derivathe boat-chair conformation --not because of de-a consequence of stabilization of the boat-chair.