Nickel-Catalyzed Synthesis of Aryl Trifluoromethyl Sulfides at Room Temperature

Copper-Catalyzed Enantioselective C(sp3 )-SCF3 Coupling of Carbon-Centered Benzyl Radicals with (Me4 N)SCF3

In contrast with the well-established C(sp2 )-SCF3 cross-coupling to forge the Ar-SCF3 bond, the corresponding enantioselective coupling of readily available alkyl electrophiles to forge chiral C(sp3 )-SCF3 bond has remained largely unexplored. We herein disclose a copper-catalyzed enantioselective radical C(sp3 )-SCF3 coupling of a range of secondary/tertiary benzyl radicals with the easily available (Me4 N)SCF3 reagent. The key to the success lies in the utilization of chiral phosphino-oxazoline-derived anionic N,N,P-ligands through tuning electronic and steric effects for the simultaneous control of the reaction initiation and enantioselectivity. This strategy can successfully realize two types of asymmetric radical reactions, including enantioconvergent C(sp3 )-SCF3 cross-coupling of racemic benzyl halides and three-component 1,2-carbotrifluoromethylthiolation of arylated alkenes under mild reaction conditions. It therefore provides a highly flexible platform for the rapid assembly of an array of enantioenriched SCF3 -containing molecules of interest in organic synthesis and medicinal chemistry.

Visible-light-promoted S-trifluoromethylation of thiophenols with trifluoromethyl phenyl sulfone

Trifluoromethyl phenyl sulfone is traditionally a nucleophilic trifluoromethylating agent. Herein, we report the first example of the use of trifluoromethyl phenyl sulfone as a trifluoromethyl radical precursor. Arylthiolate anions can form electron donor-acceptor (EDA) complexes with trifluoromethyl phenyl sulfone, which can undergo an intramolecular single electron transfer (SET) reaction under visible light irradiation, thus realizing the S-trifluoromethylation of thiophenols under photoredox catalyst-free conditions. Similar S-perfluoroethylation and S-perfluoro-iso-propylation of thiophenols are also achieved using the corresponding perfluoroalkyl phenyl sulfones.

Photoredox-Mediated, Nickel-Catalyzed Trifluoromethylthiolation of Aryl and Heteroaryl Iodides

While trifluoromethylthiolation of aryl halides has been extensively explored, the current methods require complex and/or air-sensitive catalysts. Reported here is a method employing a bench-stable Ni(II) salt and an iridium photocatalyst that can mediate the trifluoromethylthiolation of a wide range of electronically diverse aryl and heteroaryl iodides, likely via a Ni(I)/Ni(III) catalytic cycle. The reaction has broad functional group tolerance and potential for application in medicinal chemistry, as demonstrated by a late-stage functionalization approach to access (racemic)-Monepantel.

Gold (I/III)-Catalyzed Trifluoromethylthiolation and Trifluoromethylselenolation of Organohalides

The first C-SCF3 /SeCF3 cross-coupling reactions using gold redox catalysis [(MeDalphos)AuCl], AgSCF3 or Me4 NSeCF3 , and organohalides as substrates are reported. The new methodology enables a one-stop shop synthesis of aryl/alkenyl/alkynyl trifluoromethylthio- and selenoethers with a broad substrate scope (>60 examples with up to 97 % isolated yield). The method is scalable, and its robustness is evidenced by the late-stage functionalization of various bioactive molecules, which makes this reaction an attractive alternative in the synthesis of trifluoromethylthio- and selenoethers for pharmaceutical and agrochemical research and development.

Transition-Metal-Free Radical-Triggered Hydrosulfonylation and Disulfonylation Reaction of Substituted Maleimides with Sulfonyl Hydrazides

A convenient and practical hydrosulfonylation and disulfonylation of substituted maleimides was realized using sulfonyl hydrazides as the sulfur reagent and tert-butyl hydroperoxide as the oxidant. The advantages of the reactions include mild and transition-metal-free reaction conditions, good functional group tolerance, and readily available starting materials. The radical species-induced pathway is also demonstrated by mechanistic studies.

Copper catalyzed reaction of alcohols, alkyl halides and Na2S2O3: An odorless and ligand-free rout to unsymmetrical thioether synthesis

A CuI-catalyzed condensation reaction between alcohols, alkyl halides, and Na2S2O3 leading to structurally diverse thioethers is reported. A variety of alkyl halides and electron-rich benzyl alcohols were employed successfully in...

Electrochemical Trifluoromethylation of Thiophenols with Sodium Trifluoromethanesulfinate

We developed an electrochemical trifluoromethylation of thiophenols without the use of metal catalysts and oxidants. This reaction features mild reaction conditions, readily available substrate, as well as moderate to good yields. In addition, this protocol can be easily scaled up with moderate efficiency.

A general strategy for the synthesis of α-trifluoromethyl- and α-perfluoroalkyl-β-lactams via palladium-catalyzed carbonylation

β-Lactam compounds play a key role in medicinal chemistry, specifically as the most important class of antibiotics. Here, we report a novel one-step approach for the synthesis of α-(trifluoromethyl)-β-lactams and related products from fluorinated olefins, anilines and CO. Utilization of an advanced palladium catalyst system with the Ruphos ligand allows for selective cycloaminocarbonylations to give diverse fluorinated β-lactams in high yields.

Enantioselective preparation of atropisomeric biaryl trifluoromethylsulfanes via ring-opening of cyclic diaryliodoniums

Two convenient and practical methods for the synthesis of axially chiral biaryls bearing the trifluoromethylthio group are reported. A Cu-catalyzed enantioselective ring-opening reaction of cyclic diaryliodoniums with CsSCF₃ enables the direct synthesis of trifluoromethylthiolated biaryl atropisomers in high yields and enantioselectivity. For unsymmetric cyclic diaryliodoniums bearing an adjacent group to the C-I bond, a two-step procedure is required to achieve good regio- and enantioselectivity.

Catalysis with Palladium(I) Dimers

Dinuclear PdI complexes have found widespread applications as diverse catalysts for a multitude of transformations. Initially their ability to function as pre-catalysts for low-coordinated Pd0 species was harnessed in cross-coupling. Such PdI dimers are inherently labile and relatively sensitive to oxygen. In recent years, more stable dinuclear PdI -PdI frameworks, which feature bench-stability and robustness towards nucleophiles as well as recoverability in reactions, were explored and shown to trigger privileged reactivities via dinuclear catalysis. This includes the predictable and substrate-independent, selective C-C and C-heteroatom bond formations of poly(pseudo)halogenated arenes as well as couplings of arenes with relatively weak nucleophiles, which would not engage in Pd0 /PdII catalysis. This Minireview highlights the use of dinuclear PdI  complexes as both pre-catalysts for the formation of highly active Pd0 and PdII -H species as well as direct dinuclear catalysts. Focus is set on the mechanistic intricacies, the speciation and the impacts on reactivity.

Asymmetric hydrogenation of trifluoromethyl ketones: application in the synthesis of Odanacatib and LX-1031

The asymmetric hydrogenation of trifluoromethyl ketones via iridium catalysis to access chiral secondary 2,2,2-trifluoroethanols is presented. The key intermediates of Odanacatib and LX1301 were prepared with high yields and enantioselectivities.

Metal-Free Trifluoromethylthiolation of Arylazo Sulfones

A visible-light-driven protocol for the synthesis of aryl trifluoromethyl thioethers under photocatalyst- and metal-free conditions has been pursued. The procedure exploits the peculiar properties of arylazo sulfones (having electron-rich or electron-poor substituents on the (hetero)aromatic ring) as photochemical precursors of aryl radicals and S-trifluoromethyl arylsulfonothioates as easy-to-handle trifluoromethylthiolating agents.

Nickel-catalysed fluoromethylation reactions

This review highlights important developments in nickel-catalysed mono-, di- and tri-fluoromethylation, trifluoromethylthiolation and trifluoromethylselenolation.

[(bpy)CuSCF3]: A Practical and Efficient Reagent for the Construction of C–SCF3 Bonds

In this account, we summarize recent work on the direct introduction of the SCF3 group by using [(bpy)CuSCF3] as trifluoromethylthiolating reagent. A number of efficient and convenient strategies have been disclosed for the synthesis of trifluoromethylthiolated compounds, including trifluoromethylthiolation of aryl, alkenyl, and alkyl halides, and arylboronic acids. These reactions afford various trifluoromethyl sulfides in good yields.

1 Introduction

2 Synthesis of [(bpy)CuSCF3]

3 Trifluoromethylthiolation of Aryl Halides

4 Trifluoromethylthiolation of Alkenyl Halides

5 Trifluoromethylthiolation of Alkyl Halides

6 Miscellaneous

7 Conclusion

Perfluoroalkylation of Thiosulfonates: Synthesis of Perfluoroalkyl Sulfides

A practical synthesis of perfluoroalkyl sulfides is described. The method employs stable and readily accessible thiosulfonates as new electrophiles with commercial nucleophilic perfluoroalkylating reagents. The mild reaction conditions allow access to a wide variety of both aryl- and alkyl-substituted perfluoroalkyl sulfides amenable to pharmaceutical development. Furthermore, the reaction operation is straightforward, odorless, does not produce toxic wastes, and, therefore should appeal to practitioners in industrial-scale productions.

Quaternary Ammonium Trifluoromethoxide Salts as Stable Sources of Nucleophilic OCF3

The reaction of nucleophilic tertiary amines with trifluoromethyl and pentafluoroethyl methyl ethers provides quaternary ammonium trifluoromethoxide (NR₄OCF₃) and pentafluoroethoxide (NR₄OCF₂CF₃) salts, respectively, in good yields. The new trifluoromethoxide salts disclosed herein are uniquely stable for extended periods of time in both the solid state and in solution, which complements contemporary reagents. Here we describe the preparation of a range of NR₄OCF₃ salts, their long-term stability, and utility in substitution reactions.

Recent advances of dinuclear nickel- and palladium-complexes in homogeneous catalysis

In this highlight, we provide a current perspective of synthetic methodology development catalyzed by dinuclear Ni- and Pd-complexes in the past decade. The new catalytic reactivities of dinuclear Ni- and Pd-complexes are discussed.

Deoxygenative trifluoromethylthiolation of carboxylic acids

A deoxygenative trifluoromethylthiolation method produces trifluoromethyl thioesters from readily available carboxylic acids.

Here we describe a deoxygenative trifluoromethylthiolation method that yields trifluoromethyl thioesters from readily available carboxylic acids. The method is built upon an “umpolung” strategy where triphenylphosphine is used to first activate an electrophilic trifluoromethylthiolating reagent and then serves as an oxygen acceptor for the deoxygenation. The method is mild, efficient, broad-scope, and tolerant. It can be applied for the late-stage functionalization of numerous natural products and drug molecules containing a carboxylic acid group. The trifluoromethyl thioesters can be converted into trifluoromethyl thioethers by Pd-catalyzed decarbonylation.

Aryl-Fluoride Bond-Forming Reductive Elimination from Nickel(IV) Centers

The treatment of pyridine- and pyrazole-ligated Ni^II σ-aryl complexes with Selectfluor results in C(sp²)-F bond formation under mild conditions. With appropriate design of supporting ligands, diamagnetic Ni^IV σ-aryl fluoride intermediates can be detected spectroscopically and/or isolated during these transformations. These studies demonstrate for the first time that Ni^IV σ-aryl fluoride complexes participate in challenging C(sp²)-F bond-forming reductive elimination to yield aryl fluoride products.

Synthesis and Reactivity of α-Cumyl Bromodifluoromethanesulfenate: Application to the Radiosynthesis of [18 F]ArylSCF3

A highly reactive electrophilic bromodifluoromethylthiolating reagent, α-cumyl bromodifluoro-methanesulfenate 1, was prepared to allow for direct bromodifluoromethylthiolation of aryl boron reagents. This coupling reaction takes place under copper catalysis, and affords a large range of bromodifluoromethylthiolated arenes. These compounds are amenable to various transformations including halogen exchange with [18 F]KF/K222  , a process giving access to [18 F]arylSCF3 in two steps from the corresponding aryl boronic pinacol esters.

Facile synthesis of α-trifluoromethylthio phosphonium ylides with a constrained trifluoromethylthiooxide via a proton-transfer procedure

Synthesis of α-trifluoromethylthio(CF₃S–)phosphonium ylides is easily accomplished with a constrained trifluoromethylthiooxide via a proton-transfer procedure without extra base.

Nickel-catalyzed aryl trifluoromethyl sulfide synthesis: a DFT study

A Ni(i)/Ni(iii) catalytic cycle allows aryl trifluoromethyl sulfides to be obtained at room temperature from [NMe₄][SCF₃] and aryl halides.