Palladium Catalyzed Vinyltrifluoromethylation of Aryl Halides through Decarboxylative Cross-Coupling with 2-(Trifluoromethyl)acrylic Acid

Electrochemical Decarboxylative Trifluoromethylation of Cinnamic Acids Revisited: A Combined Experimental and Computational Study

β-(Trifluoromethyl)styrenes are potentially useful building blocks for the synthesis of organofluorine compounds because their electron-deficient C=C double bonds can undergo diverse transformations. One of the most practical methods for preparing β-(trifluoromethyl)styrenes is the decarboxylative trifluoromethylation of readily available cinnamic acid derivatives using the Langlois reagent as a less expensive trifluoromethyl source. We revisited the electrochemical decarboxylative trifluoromethylation of cinnamic acid derivatives to identify modified conditions that reduce the loading of the Langlois reagent without additional additives. The reaction mechanism was computationally investigated to gain insight into the dependence of the product yields on the aryl terminal groups. The synthetic utility of the obtained β-(trifluoromethyl)styrenes was demonstrated by their transformation into 4-aryl-3-(trifluoromethyl)pyrrolidines.

Palladium-Catalyzed Fluorinated Olefination of Aromatics

Palladium-mediated, ligand-promoted C-H fluorinated olefination of aromatic derivatives is reported employing 2-bromo-3,3,3-trifluoropropene (BTP) as the fluorinating reagent. Bioactive compounds, such as Isatin, exhibited excellent compatibility with this reaction, underscoring the significance of this methodology for the synthesis of important derivatives.

Visible-Light-Induced Metal-Free Decarboxylative Perfluoroalkylation of Aryl Acrylic Acids

Perfluoroalkylation is important for late-stage modification of biologically active molecules. Herein, we report a protocol for visible-light-induced perfluoroalkylation reactions of aryl acrylic acids. These reactions, which use perfluoroalkyl iodides as radical precursors and inexpensive eosin Y as a photocatalyst, proceed in a decarboxylative manner. The easy accessibility of perfluoroalkyl iodides and the broad substrate scope, mild conditions, and metal-free catalyst make this protocol applicable for the transformation of inexpensive raw materials to high-value chemicals.

Ru(II)-Catalyzed Hydroarylation of in situ Generated 3,3,3-Trifluoro-1-propyne by C-H Bond Activation: A Facile and Practical Access to β-Trifluoromethylstyrenes

In this study, a practical and straightforward synthesis of β-(E)-trifluoromethylstyrenes by ruthenium-catalyzed C-H bond activation was developed. The readily available and inexpensive 2-bromo-3,3,3-trifluoropropene (BTP), a non-ozone depleting reagent, was used as a reservoir of 3,3,3-trifluoropropyne. With this approach, the monofunctionalization of a panel of heteroarenes was possible in a safe and scalable manner (23 examples, up to 87 % yield). Mechanistic investigations and density functional theory (DFT) calculations were also conducted to get a better understanding of the mechanism of this transformation. These studies suggested that 1) a cyclometallated ruthenium complex enabled the transformation, 2) this complex exhibited high efficiency in this transformation compared to the commercially available [RuCl2 (p-cymene)]2 and 3) the mechanism proceeded through a bis-cyclometallated ruthenium intermediate for the carboruthenation step.

Copper-Catalyzed Regioselective Olefination and Trifluoromethylation of Carboxylic Acids To Give (Z)-Trifluoromethyl Enol Esters

Herein, we describe a method to produce (Z)-trifluoromethyl enol esters via the olefination and trifluoromethylation of carboxylic acids with TMSCF₃. This synthetic method uses inexpensive and easy-to-handle TMSCF₃. It employs a commercially available CuCl catalyst to transform a broad range of carboxylic acids into versatile (Z)-trifluoromethyl enol esters with good regio- and stereoselectivity. This protocol allows the concise synthesis of highly functionalized (Z)-trifluoromethyl enol esters directly from carboxylic acids.

Tungsten catalysed decarboxylative [3 + 2] cycloaddition aromatization: one-pot synthesis of trifluoromethyl-pyrrolo[2,1-a]isoquinolines with visible light irradiation

Trifluoromethyl-pyrrolo[2,1-a]isoquinolines, which are difficult to prepare via traditional methods, could be readily prepared via a tungsten-catalysed decarboxylative [3 + 2] cycloaddition aromatization process.

Recent advances in transition-metal catalyzed directed C–H functionalization with fluorinated building blocks

This review focuses on the advances in transition-metal catalyzed reactions with fluorinated building blocks via directed C–H bond activation for the construction of diverse organic molecules with an insight into the probable mechanistic pathway.

Wonderful fusion of organofluorine chemistry and decarboxylation strategy

Decarboxylation strategy has been emerging as a powerful tool for the synthesis of fluorine-containing organic compounds that play important roles in various fields such as pharmaceuticals, agrochemicals, and materials science. Considerable progress in decarboxylation has been made over the past decade towards the construction of diverse valuable fluorinated fine chemicals for which the fluorinated part can be brought in two ways. The first way is described as the reaction of non-fluorinated carboxylic acids (and their derivatives) with fluorinating reagents, as well as fluorine-containing building blocks. The second way is dedicated to the exploration and the use of fluorine-containing carboxylic acids (and their derivatives) in decarboxylative transformations. This review aims to provide a comprehensive summary of the development and applications of decarboxylative radical, nucleophilic and cross-coupling strategies in organofluorine chemistry.

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 (t_1/2 = 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.

Rhodium(III)-Catalyzed Redox-Neutral Coupling of α-Trifluoromethylacrylic Acid with Benzamides through Directed C-H Bond Cleavage

A rhodium(III)-catalyzed redox-neutral coupling of α-trifluoromethylacrylic acid with bezamides proceeds smoothly accompanied by amide-directed C-H bond cleavage to produce β-[2-(aminocarbonyl)phenyl]-α-trifluoromethylpropanoic acid derivatives. One of the products can be transformed to a trifluoromethyl substituted heterocyclic compound. In addition, the redox-neutral coupling of α-trifluoromethylacrylic acid with related aromatic substrates possessing a nitrogen-containing directing group can also be conducted under similar conditions.

Syntheses of 2-(2,2,2-trifluoroethylidene)/(2,2-difluoroethyl)-1,3-dicarbonyl compounds and their fungicidal activities

A Knoevenagel-type reaction of 1,3-diketone substrates with trifluoroacetic/difluoroacetic anhydride for the synthesis of 2-(2,2,2-trifluoroethylidene)/(2,2-difluoroethyl)-1,3-dicarbonyl compounds has been developed.

Synthesis of perinaphthenones through rhodium-catalyzed dehydrative annulation of 1-naphthoic acids with alkynes

A convenient method for the synthesis of perinaphthenones via rhodium-catalyzed dehydrative annulation of naphthoic acids with alkynes, which gave good to high yields of perinaphthenones, was developed.

Rhodium(i)-catalysed decarbonylative direct C–H vinylation and dienylation of arenes

Rh(i)-Catalyzed decarbonylative direct C–H bond vinylation and dienylation of arenes with acrylic acid and (E)-penta-2,4-dienoic acid have been developed.

Trifluoromethylation of Secondary Nitroalkanes

Using a commercially available Umemoto's reagent, the metal-free trifluoromethylation of nitroalkanes is now possible. This method provides a general, high-yielding synthesis of α-(trifluoromethyl)nitroalkanes. The quaternary α-(trifluoromethyl)nitroalkanes obtained from this transformation can be elaborated to a variety of complex nitrogen-containing molecules, including α-(trifluoromethyl)amines.

Copper-catalyzed fluoroalkylation of alkynes, and alkynyl & vinyl carboxylic acids with fluoroalkyl halides

Copper-catalyzed fluoroalkylation of alkynes and alkynyl carboxylic acids has been achieved with high functional-group tolerance and excellent regio- and stereoselectivities.

Friedel-Crafts Alkylation of Arenes with 2-Halogeno-2-CF3-styrenes under Superacidic Conditions. Access to Trifluoromethylated Ethanes and Ethenes

The formation of the corresponding benzyl cations [ArHC(+)-CH(X)CF3] takes place under protonation of E-/Z-2-halogeno-2-CF3 styrenes [ArCH═C(X)CF3, X = F, Cl, Br] in superacids. The structures of these new electrophiles were studied by means of NMR and theoretical DFT calculations. According to these data, in the case of bromo derivatives, the formed cations, most probably, exist as cyclic bromonium ions; however, in the cases of chloro and fluoro derivatives, open forms are more preferable. Subsequent reaction of these benzyl cations with arenes proceeds as Friedel-Crafts alkylation to afford 1,1-diaryl-2-halo-3,3,3-trifluoropropanes [Ar(Ar')CH-CH(X)CF3] in high yields (up to 96%) as a mixture of two diastereomers. The prepared halogenopropanes were easily converted into the corresponding mixtures of E-/Z-trifluoromethylated diarylethenes [Ar(Ar')C═CCF3] (in yields up to 96%) by dehydrohalogenation with base (KOH or t-BuOK). The mechanism of elimination (E2 and Ecb) depends on the nature of the leaving group and reaction conditions.