Thieme Chemistry Journal Awardees - Where Are They Now? Triflic Imide Catalyzed Cycloaddition Reactions

This Account summarizes our recent development of triflic imide (Tf2NH)-catalyzed cycloaddition and cascade reactions. Reactions of electron-rich olefins, possessing a silyl group, with alpha,beta-unsaturated carbonyl compounds afforded highly substituted cyclobutanes, cyclopentanes, and bicyclo [4.2.0]octanes in good to excellent yields. In the reactions, Tf2NH acts as a precatalyst to produce a strong Lewis acid, silyl triflic imide, which activates the cycloaddition reactions. Reactions of electron-rich olefins with aldimines furnished highly substituted heterocycles Such as piperidines, quinolines, and pyrrolidines. In these cases, Tf2NH acts as a strong Bronsted acid. Moreover, it was found that T2NH can catalyze more than two mechanistically distinct reactions in one pot (tandem catalysis), so that a variety of molecular skeletons can be constructed in a single operation.