Reactions of (di-)bromo-substituted CF3-allyl alcohols with/without arenes with TfOH lead to CF3-alkenes or CF3-indenes.

receptors CB 1 and CB 2 types. The most potent compound showed sub-micromolar affinity for both receptor subtypes with a 6-fold selectivity toward the CB 2 receptor with no appreciable cytotoxicity toward SHSY5Y cells.

Heteroaryl sulfonamides are important structural motifs in the medicinal and agrochemical industries. However, their synthesis often relies on the use of heteroaryl sulfonyl chlorides, which are unstable and toxic reagents....

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Reaction of 4-aryl-1,1,1-trifluorobut-3-en-2-ols [CF 3 -allyl alcohols, ArCHCHCH(OH)CF 3 ] with arenes under activation with anhydrous FeCl 3 or FSO 3 H was studied. We found that the transformation led to trifluoromethylated alkenes [Ar(Ar′)CHCHCHCF 3 ] or 1-trifluoromethylated indanes (CF 3 -indanes). The formation of these two types of reaction products strongly depends on the nucleophilicity of the starting arene and the electrophilicity of cationic intermediates generated from CF 3 -allyl alcohols under reaction conditions. Benzene, anisole, veratrole, and ortho-xylene lead exclusively to CF 3 -alkenes with an E-configuration. More π-donating polymethylated arenes (pseudocumene, mesitylene) afford only CF 3 -indanes with a predominantly cis-orientation of substituents at positions 1 and 3 of the indane ring. Meta-and para-xylenes show an intermediate behavior; they may form both CF 3 -alkenes and/or CF 3 -indanes. The mechanisms of the investigated transformations are discussed. ■ INTRODUCTIONFluorinated organic compounds have significant theoretical and practical value in chemistry, biology, medicine, and material science.1,2 Incorporation of a fluorinated moiety into a molecule often changes such important parameters as lipophilicity, metabolic activity, and bioavailability. Trifluoromethylated alkenes (styrenes) are compounds of high practical interest. Some derivatives with such fragments have been widely used for organic light-emitting diodes (OLEDs) and other material chemistry applications.3 Some trifluoromethylated alkenes attract significant attention due to important biological activity and application in medicine. Incorporation of a CF 3 group permits one to design more potent drugs. For example, Tamoxifen (Nolvadex) is the well-known triarylethylene-type antiestrogenic drug, 4 which is used in the therapy of breast cancer and for the treatment of menstrual disorders. 5Panomifene is a trifluoromethylated analogue of Tamoxifen (Figure 1). This drug demonstrated higher anticancer activity; however, quite important is the configuration of the double bond because only one diastereomer can be used.The electron-withdrawing character of fluorinated groups is another advantage, which allows one to control the selectivity of transformations of fluorinated compounds. CF 3 -substituted carbocations are very promising, but still very rare, fluorinated species exhibiting high electrophilicity and selectivity. 6 The present work is a continuation of our investigations on the electrophilic activation of alkenes 7 and alkynes. 8 In a preliminary short communication, 9 we showed that 4-phenyl-1,1,1-trifluorobut-3-en-2-ol 1a alkylated selected aromatics to afford E-4,4-diaryl-1,1,1-trifluorobut-2-enes 2 under action of various Brønsted or Lewis acids. The best results (highest yields of compounds 2) were obtained using 1 equiv of anhydrous iron trichloride FeCl 3 (Scheme 1).Interaction of CF 3 -alcohols 1 with Brønsted or Lewis acids proceeds through intermediate formation of various electrophilic spe...