Copper-Catalyzed Oxidative Trifluoromethylation of Terminal Alkenes Using Nucleophilic CF3SiMe3: Efficient C(sp3)–CF3 Bond Formation

Photoinduced metal-free trifluoro/perfluoroalkylation of heteroarenes

A practical and straightforward protocol to access trifluoromethylated/perfluoroalkylated heteroarenes via radical-type nucleophilic substitution rather than typical radical-type electrophilic substitution is described here. The substrate scope was observed to be broad and diverse-covering arenes, heteroarenes (containing N, O, S), bioactive cores, and allylic cores. Mechanistic studies confirmed a radical-mediated reaction pathway.

Trifluoromethylation of Carbonyl and Unactivated Olefin Derivatives by C(sp3 )-C Bond Cleavage

Herein, we report a Cu-mediated trifluoromethylation of carbonyl-type compounds and unactivated olefins enabled by visible-light irradiation via σ C(sp³ )-C bond-functionalization. The reaction is distinguished by its modularity, mild conditions and wide scope-even in the context of late-stage functionalization-thus offering a complementary approach en route to valuable C(sp³ )-CF₃ architectures from easily accessible precursors.

A straightforward access to trifluoromethylated natural products through late-stage functionalization

This review summarizes the applications of late-stage strategies in the direct trifluoromethylation of natural products in the past ten years, with particular emphasis on the reaction model of each method.

Photo-Promoted Decarboxylative Alkylation of α,β-Unsaturated Carboxylic Acids with ICH2CN for the Synthesis of β,γ-Unsaturated Nitriles

An efficient, catalyst/photocatalyst-free, and cost-effective methodology for the decarboxylative alkylation of α,β-unsaturated carboxylic acids to synthesize β,γ-unsaturated nitriles has been developed. The reaction proceeded in an environmentally benign atmosphere of blue light-emitting diode irradiation with K₂CO₃ and water at room temperature. The methodology worked for a wide range of substrates (22 examples) with up to 83% yield. The protocol is also compatible for gram-scale synthesis.

Photoredox-Catalyzed Selective Synthesis of Allylic Perfluoroalkanes from Alkenes

We report herein a novel photoredox-catalyzed synthesis of allylic trifluoromethanes. The use of sulfilimino iminium as a source of trifluoromethyl radicals proves crucial to achieving high selectivity. Importantly, both styrene derivatives and unactivated alkenes are for the first time suitable partners for this process. The mild reaction conditions are compatible with a variety of functional groups. Remarkably, this method is readily broadened to other perfluoroalkyl groups (R_F =CFCl₂ , CF₂ Br, C₄ F₉ ). An extensive mechanistic study is also provided.

Silver-Mediated Perfluoroalkylation of Terminal Alkynes with Perfluoroalkyl Iodides

The incorporation of a perfluoroalkyl group (R_F) into drug candidates has become an increasingly important strategy in drug molecule design. In this study, the silver-mediated perfluoroalkylation reaction based on the addition-elimination process of terminal alkynes which was initiated by a perfluoroalkyl radical to form a C(sp)-R_F bond has been developed. The reaction proceeds under mild conditions using readily available, low-cost perfluoroalkyl iodides as the sources of the R_F group. This method allows access to a variety of perfluoroalkylated alkynes.

Radical Pentafluoroethylation of Unactivated Alkenes Using CuCF2CF3

We have found that the CuCF₂CF₃ complex generated from low-cost pentafluoroethane is a convenient and practical source for the CF₂CF₃ radical under aerobic conditions at room temperature. Using this system, readily available unactivated alkenes can be pentafluoroethylated to provide novel allylic CF₂CF₃ compounds with excellent E-selectivity and functional group tolerability. Mechanistic studies including TEMPO-CF₂CF₃ trapping and radical clock experiments provided strong evidence for radical pathways, offering a new opportunity for copper-mediated radical perfluoroalkylation.

Copper-Catalyzed Annulation-Cyanotrifluoromethylation of 1,6-Enynes Toward 1-Indanones via a Radical Process

A new Cu(II)-catalyzed annulation-cyanotrifluoromethylation of 1,6-enynes with Togni's reagent and trimethylsilyl cyanide (TMSCN) has been established, enabling the direct construction of trifluoromethylated 1-indanones with an all-carbon quaternary center in good yields. This reaction was performed by using low-cost Cu(OTf)₂ as the catalyst and Togni's reagent as both the radical initiator and a CF₃ source, providing an efficient protocol for building up an 1-indanone framework with wide functional group compatibility. The reaction mechanism was proposed through a radical triggered addition/5-exo-dig cyclization/oxidation/nucleophilic cascade.

Copper-Catalyzed Oxidative Trifluoromethylation of Terminal Alkenes Using AgCF3

A mild and convenient reaction for oxidative trifluoromethylation of terminal alkenes was developed using in situ generated AgCF₃ in the presence of a copper catalyst. The reaction proceeded under an air atmosphere to afford trifluoromethylated allylic compounds in moderate to good yield. This reaction, with no need for highly hygroscopic or corrosive reagents, features not only a simple operation but also various functional group tolerances.

An efficient and facile strategy for trifluoromethylation and perfluoroalkylation of isoquinolines and heteroarenes

An effective and regioselective strategy for trifluoromethylation and perfluoroalkylation of isoquinolines and heteroarenes was developed.

Metal-Free Construction of the C(sp3)-CF3 Bond: Trifluoromethylation of Hydrazones with Togni's Reagent under Mild Conditions

A metal-free trifluoromethylation of hydrazones with Togni's reagent under mild conditions was developed. Various functional groups including ester, methoxy, dimethoxy, nitro, halogen, and heterocyclic compounds were tolerated. This simple and green strategy provides a practical tool to construct C(sp³)-CF₃ bonds.

Aryltrifluoromethylative cyclization of unactivated alkenes by the use of PhICF3Cl under catalyst-free conditions

A concise and catalyst-free aryltrifluoromethylative cyclization of unactivated alkenes has been developed herein. The use of PhICF3Cl as a powerful trifluoromethylating agent allows easy transformations. A set of trifluoroethylated carbocycles and aza-hereocycles were efficiently synthesized in good yield and selectivity. A broad substrate scope, mild reaction conditions, and easy operation would make this method well-suited for applications.

Visible light enabled γ-trifluoromethylation of Baylis–Hillman acetates: stereoselective synthesis of trisubstituted alkenes

Metal-free γ-trifluoromethylation of Baylis–Hillman acetates is reported using Langlois’ reagent under visible light photoredox catalysis.

Catalyst-free and selective trifluoromethylative cyclization of acryloanilides using PhICF3Cl

Trifluoromethylative cyclization and biscyclization reactions of acryloanilides efficiently occurred under catalyst-free conditions.

Copper-Catalyzed Perfluoroalkylation of Allyl Phosphates with Stable Perfluoroalkylzinc Reagents

A general and practical method for copper-catalyzed cross-coupling of allyl phosphates with stable perfluoroalkylzinc reagents has been developed. The reaction proceeds under mild reaction conditions with high efficiency, good functional group tolerance, and high regio- and stereoselectivities and provides general, straightforward, and useful access to allyl-perfluoroalkyl compounds. Preliminary mechanistic studies reveal that the allyl copper intermediate may be involved in the catalytic cycle.

Synthesis of CF3CH2-Containing Indolines by Transition-Metal-Free Aryltrifluoromethylation of Unactivated Alkenes

With an unactivated double bond as the radical acceptor, allyl amines underwent a metal-free trifluoromethylation/cyclization cascade with CF₃SO₂Na (Langlois' reagent), affording CF₃CH₂-containing indolines and tetrahydroisoquinolines, whose practical syntheses are significant challenges. This protocol features mild conditions, low cost, and a broad substrate scope.

A redox-economical synthesis of trifluoromethylated enamides with the Langlois reagent

A redox-economical strategy for the synthesis of trifluoromethylated enamides using copper catalysis is reported. The reaction employs the inexpensive Langlois reagent (CF₃SO₂Na) and takes place without the need of an external oxidant. The trifluoromethylated enamide products can easily be converted into the corresponding ketone, saturated amide or oxazole.

Direct oxidative isoperfluoropropylation of terminal alkenes via hexafluoropropylene (HFP) and silver fluoride

Hexafluoropropylene was used directly in a reaction of copper-mediated oxidative isoperfluoropropylation of unactivated terminal alkenes. This strategy provides a general and straightforward way for the preparation of allylic isoperfluoropropylated compounds.

N-Heterocycle-Forming Amino/Carboperfluoroalkylations of Aminoalkenes by Using Perfluoro Acid Anhydrides: Mechanistic Studies and Applications Directed Toward Perfluoroalkylated Compound Libraries

This work describes a practical and efficient method for synthesizing a diverse array of perfluoroalkylated amines, including N-heterocycles, to afford perfluoroalkylated chemical libraries as potential sources of drug candidates, agrochemicals, and probe molecules for chemical-biology research. Perfluoro acid anhydrides, which are commonly used in organic synthesis, were employed as a perfluoroalkyl source for intramolecular amino- and carbo-perfluoroalkylations of aminoalkenes, affording perfluoroalkylated N-heterocycles, including: aziridines, pyrrolidines, benzothiazinane dioxides, indolines, and hydroisoquinolinones. Diacyl peroxides were generated in situ from the perfluoro acid anhydrides with urea·H₂O₂, and allowed to react with aminoalkenes in the presence of copper catalyst to control the product selectivity between amino- and carbo-perfluoroalkylations. To illustrate the synthetic utility of bench-stable trifluoromethylated aziridine, which was prepared on a gram scale, we used it to synthesize a wide variety of trifluoromethylated amines including complex molecules, such as trifluoromethylated tetrahydroharmine and spiroindolone. A mechanistic study of the role of the copper catalyst in the aminotrifluoromethylation of allylamine suggested that Cu(I) accelerates CF₃ radical formation via decomposition of diacyl peroxide, which appears to be the turnover-limiting step, while Cu(II) controls the product selectivity.

Transforming Olefins into γ,δ-Unsaturated Nitriles through Copper Catalysis

We have developed a strategy to transform olefins into homoallylic nitriles through a mechanism that combines copper catalysis with alkyl nitrile radicals. The radicals are easily generated from alkyl nitriles in the presence of the mild oxidant di-tert-butyl peroxide. This cross-dehydrogenative coupling between simple olefins and alkylnitriles bears advantages over the conventional use of halides and toxic cyanide reagents. With this method, we showcase the facile synthesis of a flavoring agent, a natural product, and a polymer precursor from simple olefins.

Transition-metal-free synthesis of β-trifluoromethylated enamines with trifluoromethanesulfinate

Direct olefinic C–H trifluoromethylation of enamines is developed under transition metal-free conditions by using Langlois' reagent (NaSO₂CF₃).

Copper-catalyzed gem-difluoromethylenation of C(sp2)–H bonds of alkenes

Copper-catalyzed gem-difluoromethylenation of the C(sp²)–H bonds of alkenes has been developed. This protocol is the first to efficiently achieve gem-difluoromethylenation of C(sp²)–H bonds of unactivated aliphatic terminal olefins and is applied in gem-difluoromethylenation/cyclization of alkenes.

The Role of Ate Complexes in the Copper-Mediated Trifluoromethylation of Alkynes

Trifluoromethylation reactions have recently received increased attention because of the beneficial effect of the trifluoromethyl group on the pharmacological properties of numerous substances. A common method to introduce the trifluoromethyl group employs the Ruppert-Prakash reagent, that is, Si(CH3 )3 CF3 , together with a copper(I) halide. We have applied this method to the trifluoromethylation of aromatic alkynes and used electrospray-ionization mass spectrometry to investigate the mechanism of these reactions in tetrahydrofuran, dichloromethane, and acetonitrile as well as with and without added 1,10-phenanthroline. In the absence of the alkyne component, the homoleptic ate complexes [Cu(CF3 )2 ](-) and [Cu(CF3 )4 ](-) were observed. In the presence of the alkynes RH, the heteroleptic complexes [Cu(CF3 )3 R](-) were detected as well. Upon gas-phase fragmentation, these key intermediates released the cross-coupling products R-CF3 with perfect selectivity. Apparently, the [Cu(CF3 )3 R](-) complexes did not originate from homoleptic cuprate anions, but from unobservable neutral precursors. The present results moreover point to the involvement of oxygen as the oxidizing agent.