The 1H and 13C NMR chemical shifts of cyclopentane-fused cis-azetidinone (cis-azabicyclo[3.2.0]heptan-7-one) were determined with the help of full spectral analysis. The geometry and electronic structure of the molecule were investigated at both the RHF and the B3LYP level with different basis sets. The NMR data were calculated by means of the GIAO, CSGT and IGAIM methods. All quantum-chemical calculations, including those of NMR data, were performed by ab initio level RHF and DFT methods. The geometry optimization resulted in an envelope-type conformation, while the four-membered heterocycle proved to be planar. Excellent agreement between the theoretical and experimental results was found for the RHF-level 1H chemical shifts and for the B3LYP-type 13C chemical shifts. The experimental spectra revealed equivalent methylene protons at position 5, indicating that the cyclopentane ring has a high degree of conformational freedom at this carbon.
|Number of pages||8|
|Publication status||Published - dec. 1 2001|
ASJC Scopus subject areas
- Organic Chemistry