3,4-DI-TERT-BUTYL-1,3,4-OXADIAZOLIDINE - SYNTHESIS AND STRUCTURE

3,4-Di-tert-butyl-1,3,4-oxadiazolidine 1d has been synthesized and for the first time fully characterized; an envelope conformation has been established by X-ray diffraction analysis of 1d in the crystal, and a semi-chair conformation with a trans-diaxial orientation of Bu(t) gro ups determined by NMR spectroscopy in solution and, additionally, by M NDO and ab initio calculations in the gas phase; the lower limit of th e barrier to sterically-hindered nitrogen inversion was evaluated as D elta G double dagger > 22.8 kcal mol(-1) at 130 degrees C.