Umemoto’s Reagent

Introduction

The trifluoromethyl group is an important structural moiety in diverse organic molecules due to the significant unique features that trifluoromethylated compounds have in pharmaceuticals, agricultural chemicals, and functional materials.[ ¹ ]

The first electrophilic trifluoromethylating reagent, di­aryl(trifluoromethyl) sulfonium salt, Ar₂S⁺CF₃SbF₆ ⁻, was achieved by Yagupolskii and co-workers in 1984.[ ² ] In 1990, Umemoto and co-workers developed a new series of electrophilic trifluoromethylating reagents, for example, (trifluoromethyl)dibenzoheterocyclic salts with fine tuning of their electrophilicity.[3] [4] [5] The reagents are achieved via an oxidation of the starting materials (sulfides, selenides or telluride) followed by a cyclization or a direct fluorination (Scheme [1]). As an efficient electrophilic trifluoromethylating agent, Umemoto’s reagent has been successfully applied in the trifluoromethylation of a wide range of nucleophiles including carbanions, silyl enol ethers, enamines, phenols, anilines, phosphines and thiolates. The combination of Umemoto’s reagent with a chiral base provided a useful entry to the enantioselective electrophilic trifluoromethylation. More recently, the direct C–H bond trifluoromethylation has been achieved by using the Umemoto’s reagent and transition-metal catalysis, thus expanding the scope of current popular C–H bond activations.

Umemoto’s reagents are operational simple, high stabile at ambient conditions and commercially available.

Scheme 1 Umemoto’s reagent

• References

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