1,1,1,3,3,3-Hexafluoroisopropanol-PromotedSynthesisof Structurally Diverse Alkylidene-4-thiazolidinones/selenazolidinonesInvolving an Azaoxyallyl Cation

A one-pot process involving cycloaddition of the azaoxyallyl cation with thioamide and a synchronous E1-type elimination of the C2 amino group from the cycloadduct is disclosed, leading to diverse alkylidene-4-thiazolidinones. Amine elimination under acid-free conditions or without quaternization and forging a stereoselective olefin formation were among the interesting reactivity traits revealed through the present work. Conjugated thioamide permitted side-chain branching through a three-component process. Access to spirooxindolyl thiazolidinones and selenazolidinones adds further value to the process.