Mechanism and Stereochemical Implications of the Reaction of an Oxazolium-5-oxide with 1,2-Dicyanocyclobutene. An AM1 Study

Oxazolium-5-oxide (1) cycloadds to 1,2-dicyanocyclobutene (2) to give the imino-acid (3) and the dihydroazepine (4). AM1 molecular orbital calculations were carried out on the reaction in order to rationalize the observed stereochemistry of 3 and to further elucidate the overall reaction mechanism leading to 3 and 4