Cyclic Thioanhydrides:Linchpins for Multicomponent Coupling Reactions Based on the Reaction of Thioacids with Electron-Deficient Sulfonamides and Azides

摘要

Reaction of cyclic thioanhydrides with amines affords amides functionalized with thioacids,which can be trapped in situ with electron-deficient azides or,preferably,2,4-dinitrobenzenesulfonamides.In this manner the cyclic thioanhydride serves as a linchpin in a three-component coupling sequence.The use of thiomaleic anhydride and a bifunctional nucleophile extends the process to heterocycle synthesis,while a cyclic thioanhydride prepared from aspartic acid directly provides N-functionalized asparagine derivatives.