One-Step Assembly of Functionalized Morpholinones and 1,4-Oxazepane-3-ones via [3 + 3]- and [3 + 4]-Annulation of Aza-Oxyallyl Cation and Amphoteric Compounds

A new [3 + 3]- and [3 + 4]-annulation strategy involving
azaoxyallyl
cation and [1,m]-amphoteric compounds (m = 3,4) is presented. This concise method enables easy assembly of
functionalized saturated N-heterocycles, comprised of six-and seven-membered
rings and is of high significance in the context of drug discovery
approaches. This reaction also represents a new trapping modality
of the azaoxyallyl cation with amphoteric agents of different chain
lengths that consist of a heteroatom nucleophilic site and a π-electrophilic
site.