Abstract The synthesis of quinuclidine-3-spiro-5′-oxazolidine-2′, 4′-dione, quinuclidine- 3-spiro-5′-hydantoin, and some 3′-derivatives is described. Based on the data from 1 H and 13 C-nmr spectra the structure of the above mentioned compounds is established. A relationship between second order effects in 13 C-nmr spectra and HCCH dihedral angles is deduced.