The natural bond orbital analysis suggested that the stability of the iminium should result from the stereoelectronic effect (hyperconjugation) attributed to their own structures.

The Journal of organic chemistry

The treatment of morphinan 1 with NaH and MsCl provided very stable iminium salt 7 possessing propellane skeleton. One of the synthesized iminium salts 7, isobutyl derivative 7b, was crystallized and its structure was determined by X-ray crystallography. The natural bond orbital analysis suggested that the stability of the iminium should result from the stereoelectronic effect (hyperconjugation) attributed to their own structures.

The natural bond orbital analysis suggested that the stability of the iminium should result from the stereoelectronic effect (hyperconjugation) attributed to their own structures.

Synthesis of a stable iminium salt and propellane derivatives.