SummarySince the discovery by Yagupolskii and co-workers that S-trifluoromethyl diarylsulfonium salts are effective for the trifluoromethylation of thiophenolates, the design and synthesis of electrophilic trifluoromethylating reagents have been extensively researched in both academia and industry, due to the significant unique features that trifluoromethylated compounds have in pharmaceuticals, agricultural chemicals, and functional materials. Several effective reagents have been developed by the groups of Yagupolskii, Umemoto, Shreeve, Adachi, Magnier, Togni and Shibata. Due to the high stability and reactivity of these reagents, a series of Umemoto reagents, Togni reagent and Shibata reagent are now commercially available. In this review, we wish to briefly provide a historical perspective of the development of so-called “shelf-stable electrophilic trifluoromethylating reagents”, although this field is in constant development.

Chef im Ring: Die S‐(Trifluormethyl)benzo[b]thiophenium‐Salze 1, Analoga für Yagupolskii‐Umemoto‐Reagentien, wurden durch eine neuartige Trifluormethansulfonsäure‐katalysierte intramolekulare Cyclisierung aus ortho‐Ethinylaryltrifluormethylsulfanen 2 synthetisiert. 1 j erwies sich als besonders nützlich in der elektrophilen Trifluormethylierung von β‐Ketoestern und Dicyanalkylidenen.

No abstract

Chiral nonracemic guanidines act as Brønsted bases to generate guanidinium enolates for the enantioselective electrophilic trifluoromethylation of beta-keto esters by means of S-(trifluoromethyl)dibenzothiophenium tetrafluoroborate (Umemoto reagent) with good enantioselectivity of 60-70% range. Despite the fact that the ees are still improvable, the model reported in this work could spark the imagination of chemists to design new chiral bases to improve the stereochemical outcome.