Base‐catalyzed [3 + 2]/[4 + 2]‐annulations of cyclic N‐sulfimines with γ‐ and δ‐sulfonamido/hydroxy‐α,β‐unsaturated carbonyls: Stereoselective synthesis of imidazolidines, oxazolidines, hexahydropyrimidines, and 1,3‐oxazinanes

Abstract

A highly efficient and straightforward synthetic methodology has been established for the preparation of imidazolidine derivatives through the [3 + 2]‐annulation of cyclic N‐sulfimines. This reaction involves the reaction of cyclic N‐sulfimines and γ‐sulfonamido‐α,β‐unsaturated carbonyl compounds, with Cs2CO3 serving as the catalyst. The outcome is a diverse range of imidazolidine derivatives with remarkable yields and stereoselectivities. In addition, the [4 + 2]‐annulation between cyclic N‐sulfimines and δ‐sulfonamido‐α,β‐unsaturated carbonyl compounds, catalyzed by Et3N, has been successfully applied for the synthesis of stereoselective hexahydropyrimidines. Furthermore, the base‐catalyzed annulation of cyclic N‐sulfimines with γ‐ and δ‐hydroxy‐α,β‐unsaturated carbonyl compounds has proven to be a reliable method for the synthesis of oxazolines and 1,3‐oxazinanes.