Bicyclic Imides with Bridgehead Nitrogen. Synthesis and X-ray Crystal Structure of a Bicyclic 2,4-Oxazolidinedione

Article abstract of DOI:10.1021/jo00200a020

The first successful synthesis of bicyclic 2,4-oxazolidinediones with bridgehead nitrogen, examples of anti-Bredt imides, was accomplished.The synthetic approaches involved three homologous bridging sizes, and the smallest product capable of preparation was 1-aza-8,9-dioxo-7-oxa-6-phenylbicyclo<4.2.1>nonane, for which the structure was verified by X-ray diffraction.Also prepared was 1-aza-9,10-dioxo-8-oxa-7-phenylbicyclo<5.2.1>decane.These results were accurately predicted by using anti-Bredt olefins as models, suggesting that resonance effects may be essential for the stability of anti-Bredt imides.