Rapid Syntheses of [11C]Arylvinyltrifluoromethanes through Treatment of (E)-Arylvinyl(phenyl)iodonium Tosylates with [11C]Trifluoromethylcopper(I).

We report a method for labeling arylvinyltrifluoromethanes with carbon-11 (t1/2 = 20.4 min) as representatives of a new radiolabeled chemotype that has potential for developing radiotracers for biomedical imaging with positron emission tomography. Treatment of (E)-arylvinyl(phenyl)iodonium tosylates (1a-1k) with [11C[CuCF3 gave the corresponding [11C]arylvinyltrifluoromethanes ([11C]2a-[11C]2k) in high radiochemical yields (90-97%) under rapid (2 min) and mild (60 °C) conditions.

A Gas Phase Route to [18F]fluoroform with Limited Molar Activity Dilution.

Positron emission tomography (PET) is an important imaging modality for biomedical research and drug development. PET requires biochemically selective radiotracers to realize full potential. Fluorine-18 (t1/2 = 109.8 min) is a major radionuclide for labeling such radiotracers but is only readily available in high activities from cyclotrons as [18F]fluoride ion. [18F]fluoroform has emerged for labeling tracers in trifluoromethyl groups. Prior methods of [18F]fluoroform synthesis used difluoro precursors in solution and led to high dilution with carrier and low molar activity (Am). We explored a new approach for the synthesis of [18F]fluoroform based on the radiosynthesis of [18F]fluoromethane from [18F]fluoride ion and then cobaltIII fluoride mediated gas phase fluorination. We estimate that carrier dilution in this process is limited to about 3-fold and find that moderate to high Am values can be achieved. We show that [18F]fluoroform so produced is highly versatile for rapidly and efficiently labeling various chemotypes that carry trifluoromethyl groups, thereby expanding prospects for developing new PET radiotracers.

Simple and Clean Photoinduced Aromatic Trifluoromethylation Reaction.

We describe a simple, metal- and oxidant-free photochemical strategy for the direct trifluoromethylation of unactivated arenes and heteroarenes under either ultraviolet or visible light irradiation. We demonstrated that photoexcited aliphatic ketones, such as acetone and diacetyl, can be used as promising low-cost radical initiators to generate CF3 radicals from sodium triflinate efficiently. The broad utility of this strategy and its benefit to medicinal chemistry are demonstrated by the direct trifluoromethylation of unprotected bidentate chelating ligand, xanthine alkaloids, nucleosides, and related antiviral drug molecules.

Gem-difluoromethylated and trifluoromethylated derivatives of DMDP-related iminosugars: synthesis and glycosidase inhibition.

Gem-difluoromethylated and trifluoromethylated derivatives of DMDP-related iminosugars have been synthesized from cyclic nitrones 12, 13, 18, ent-18 or 23 and nitrone-derived aldehydes 20 or ent-20. The fluorinated iminosugars were assayed against various glycosidases, and ent-8 showed moderate but selective α-l-rhamnosidase inhibition. Difluoro or trifluoro units influenced the inhibitory activities of iminosugars in a more complex manner than single fluoro substitution. This may be correlated with their highly hydrophobic character and strong electron-withdrawing effect.

Highly regio- and diastereoselective synthesis of CF3-substituted lactones via photoredox-catalyzed carbolactonization of alkenoic acids.

Trifluoromethylative lactonization of both terminal and internal alkenoic acids by photoredox catalysis has been developed. The use of a Ru photocatalyst and Umemoto's reagent as a CF3 source is key in the present carbolactonization. This is the first example of a highly endo- and diastereoselective synthesis of CF3-substituted five-, six-, and seven-membered ring lactones from internal alkenoic acids.

Efficient synthesis of [18F]trifluoromethane and its application in the synthesis of PET tracers.

A new strategy towards [(18)F]trifluoromethyl-containing compounds is developed. [(18)F]trifluoromethane is synthesised in a fast and efficient manner and subsequently used in the reaction with aldehydes and ketones forming [(18)F]trifluoromethyl carbinols in good yields.

Sequential electrophilic trifluoromethanesulfanylation-cyclization of tryptamine derivatives: synthesis of C(3)-trifluoromethanesulfanylated hexahydropyrrolo[2,3-b]indoles.

A practical and efficient synthesis of C(3)-trifluoromethanesulfanylated hexahydropyrrolo[2,3-b]indoles 5 from tryptamine derivatives was described. The features of this synthesis included electrophilic activation of C(3) of tryptamine derivatives with "CF(3)S(+)" and cascade ring cyclization by carbamate nucleophile attacking at C(2). Surprisingly, when Lewis acid (BF(3)·OEt(2)) was used as activator instead of proton acid (TsOH·H(2)O) for the electrophilic trifluoromethanesulfanylation of tryptamine derivatives, the uncyclized product 6 was formed preferentially. This sequential trifluoromethanesulfanylation-cyclization protocol was used to synthesize several pyrrolidinoindolinic alkaloid analogues. The cytotoxicity activities of these trifluoromethanesulfanylated alkaloid analogues were evaluated against three cancer cell lines (K562, HeLa, L929).