Copper-Catalyzed Trifluoromethyl Thiolation-Mild and Efficient Synthesis of Trifluoromethyl Thioethers

Asymmetric Synthesis of SCF3-Substituted Alkylboronates by Copper-Catalyzed Hydroboration of 1-Trifluoromethylthioalkenes

A synthetic method for preparation of optically active trifluoromethylthio (SCF3) compounds by a copper-catalyzed regio- and enantioselective hydroboration of 1-trifluoromethylthioalkenes with H-Bpin has been developed. The enantioselective hydrocupration of an in situ generated CuH species and subsequent boration reaction generate a chiral SCF3-containing alkylboronate, of which Bpin moiety can be further transformed to deliver various optically active SCF3 molecules. Computational studies suggest that the SCF3 group successfully controls the regioselectivity in the reaction.

Organoselenium Compounds: Chemistry and Applications in Organic Synthesis

Selenium, originally described as a toxin, turns out to be a crucial trace element for life that appears as selenocysteine and its dimer, selenocystine. From the point of view of drug developments, selenium-containing drugs are isosteres of sulfur and oxygen with the advantage that the presence of the selenium atom confers antioxidant properties and high lipophilicity, which would increase cell membrane permeation leading to better oral bioavailability. In this article, we have focused on the relevant features of the selenium atom, above all, the corresponding synthetic approaches to access a variety of organoselenium molecules along with the proposed reaction mechanisms. The preparation and biological properties of selenosugars, including selenoglycosides, selenonucleosides, selenopeptides, and other selenium-containing compounds will be treated. We have attempted to condense the most important aspects and interesting examples of the chemistry of selenium into a single article.

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.

Direct Synthesis of Disubstituted Trifluoromethylthiolated Alkenes

In the field of organofluorine chemistry, the quest for emergent fluorinated groups is in high demand. In particular, the scientific community has shown special interest in the SCF3 residue thanks to its unique properties. Indeed, over the last decade, the SCF3 group has become a pivotal fluorinated moiety, as demonstrated by several SCF3-containing compounds of interest, and, related to that, the steadily increasing number of synthetic methods that are available to access such molecules. In this Short Review, the main advances made for the synthesis of trifluoromethylthiolated disubstituted alkenes will be discussed and highlighted.

1 Introduction

2 Trifluoromethylthiolation of Prefunctionalized Alkenes

3 Direct C–H Trifluoromethylthiolation of Alkenes

4 Trifluoromethylthiolation of Miscellaneous Derivatives

5 Conclusion

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.

Chlorotrifluoromethylthiolation of Sulfur Ylides for the Formation of Tetrasubstituted Trifluoromethylthiolated Alkenes

Tetrasubstituted trifluoromethylthiolated alkenes can be accomplished directly through the chlorotrifluoromethylthiolation of sulfur ylides utilizing nucleophilic halide reagent and electrophilic SCF₃ reagent. This cascade reaction is mild, highly practical, easy to manipulate, uses catalyst-free conditions, and demonstrates a wide substrate range with excellent functional group tolerance, furnishing E-selective products in good to high yields. The synthetic utility of this approach is documented through gram-scale preparation and late-stage modification of pharmaceutically relevant compounds, making it suitable for drug discovery.

Geometrically Selective Denitrative Trifluoromethylthiolation of β-Nitrostyrenes with AgSCF3 for (E)-Vinyl Trifluoromethyl Thioethers

An efficient copper(II)-promoted denitrative trifluoromethylthiolation under mild reaction conditions has been developed for vinyl trifluoromethyl thioethers to construct C_vinyl-SCF₃ bonds with stable AgSCF₃ as a source of the trifluoromethylthio. This reaction system tolerates a broad range of functional groups to commendably achieve a high product yield and excellent stereoselectivity of E/Z.

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.

Synthesis of aryl α,α-difluoroethyl thioethers a novel structure motif in organic chemistry, and extending to aryl α,α-difluoro oxyethers

A method for the preparation of aryl α,α-difluoroethyl thioethers (ArSCF₂CH₃) is reported and the synthesis approach is extended to aryl α,α-difluoroethyl oxygen ethers.

Bismuth(III)-Promoted Trifluoromethylthiolation of Pyrazolin-5-ones with Trifluoromethanesulfenamide

An efficient and facile method for the synthesis of trifluoromethylthiolated 5-hydroxy-1H-pyrazole derivatives by reaction of pyrazolin-5-ones with trifluoromethanesulfenamide (PhNHSCF₃) in the presence of BiCl₃ was developed.

Synthesis of o-Methyl Trifluoromethyl Sulfide Substituted Benzophenones via 1,2-Difunctionalization of Aryne by Insertion into the C-C Bond

An efficient process for the preparation of valuable o-methyl trifluoromethyl sulfide substituted benzophenones has been developed. The transition-metal-free method features insertion of aryne into a C-C σ-bond under mild reaction conditions for the first time to achieve ortho-difunctionalized arenes containing a pharmaceutically important trifluoromethylthio functional group. A wide substrate scope has been demonstrated for the developed protocol.

Tandem trifluoromethylthiolation/aryl migration of aryl alkynoates to trifluoromethylthiolated alkenes

The oxidative trifluoromethylthiolation of aryl alkynoates with AgSCF₃ provided a new access to trifluoromethylthiolated alkenes.

N-Trifluoromethylthio-dibenzenesulfonimide: A Shelf-Stable, Broadly Applicable Electrophilic Trifluoromethylthiolating Reagent

The super electrophilicity of a shelf-stable, easily prepared trifluoromethylthiolating reagent N-trifluoromethylthio-dibenzenesulfonimide 7 was demonstrated. Consistent with the theoretical prediction, 7 exhibits reactivity remarkably higher than that of other known electrophilic trifluoromethylthiolating reagents. In the absence of any additive, 7 reacted with a wide range of electron-rich arenes and activated heteroarenes under mild conditions. Likewise, reactions of 7 with styrene derivatives can be fine-tuned by simply changing the reaction solvents to generate trifluoromethylthiolated styrenes or oxo-trifluoromethylthio or amino-trifluoromethylthio difunctionalized compounds in high yields.

Enantioselective Trifluoromethylthiolating Lactonization Catalyzed by an Indane-Based Chiral Sulfide

Enantioselective trifluoromethylthiolation, especially of alkenes, is a challenging task. In this work, we have developed an efficient approach for enantioselective trifluoromethylthiolating lactonization by designing an indane-based bifunctional chiral sulfide catalyst and a shelf-stable electrophilic SCF3 reagent. The desired products were formed with diastereoselectivities of >99:1 and good to excellent enantioselectivities. The transformation represents the first enantioselective trifluoromethylthiolation of alkenes and the first enantioselective trifluoromethylthiolation that is enabled by a catalyst with a Lewis basic sulfur center.

Regioselective ortho-trifluoromethylthiolation of 2-arylbenzo[d]thiazole via tandem substrate-assisted C-H iodination and trifluoromethylthiolation

A mild and efficient tandem benzo[d]thiazole directed C-H iodination and trifluoromethylthiolation for the synthesis of ortho-trifluoromethylthiolated 2-arylbenzo[d]thiazoles have been developed using AgSCF3 as a coupling partner. The reaction exhibits a diverse array of functional group tolerance giving the desired products in good to excellent yields. Regioselective trifluoromethylthiolation was observed at the less sterically hindered site when the phenyl ring of the substrate possesses a methyl group at its meta position.

Visible-Light-Promoted Trifluoromethylthiolation of Styrenes by Dual Photoredox/Halide Catalysis

Herein, we report a new visible-light-promoted strategy to access radical trifluoromethylthiolation reactions by combining halide and photoredox catalysis. This approach allows for the synthesis of vinyl-SCF3 compounds of relevance in pharmaceutical chemistry directly from alkenes under mild conditions with irradiation from household light sources. Furthermore, alkyl-SCF3-containing cyclic ketone and oxindole derivatives can be accessed by radical-polar crossover semi-pinacol and cyclization processes. Inexpensive halide salts play a crucial role in activating the trifluoromethylthiolating reagent towards photoredox catalysis and aid the formation of the SCF3 radical.

Convenient synthesis of pentafluoroethyl thioethers via catalytic Sandmeyer reaction with a stable fluoroalkylthiolation reagent

A Sandmeyer type process is disclosed that allows the straightforward synthesis of pentafluoroethyl thioethers from aromatic amines and tetramethylammonium pentafluoroethylthiolate.

Iodine-mediated regioselective synthesis of vinyl triflones from styrenes with CF3SO2Na

The iodine-mediated reaction of styrenes and CF₃SO₂Na proceeded regioselectively to give various potentially useful vinyl triflones.

Efficient catalytic α-trifluoromethylthiolation of aldehydes

An efficient organocatalytic method for α-trifluoromethylthiolation of aldehydes has been developed.

Photoorganocatalysed and visible light photoredox catalysed trifluoromethylation of olefins and (hetero)aromatics in batch and continuous flow

Trifluoromethylation of olefins and (hetero)aromatics with sodium triflinate as CF₃source and readily accessible benzophenone derivatives as photosensitisers has been developed in batch and flow.

Nickel-catalyzed trifluoromethylthiolation of Csp2-O bonds

While nickel catalysts have previously been shown to activate even the least reactive Csp²-O bonds, i.e. aryl ethers, in the context of C-C bond formation, little is known about the reactivity limits and molecular requirements for the introduction of valuable functional groups under homogeneous nickel catalysis. We identified that due to the high reactivity of Ni-catalysts, they are also prone to react with existing or installed functional groups, which ultimately causes catalyst deactivation. The scope of the Ni-catalyzed coupling protocol will therefore be dictated by the reactivity of the functional groups towards the catalyst. Herein, we showed that the application of computational tools allowed the identification of matching functional groups in terms of suitable leaving groups and tolerated functional groups. This allowed for the development of the first efficient protocol to trifluoromethylthiolate Csp²-O bonds, giving the mild and operationally simple C-SCF₃ coupling of a range of aryl, vinyl triflates and nonaflates. The novel methodology was also applied to biologically active and pharmaceutical relevant targets, showcasing its robustness and wide applicability.

Diaryl Selenide Catalyzed Vicinal Trifluoromethylthioamination of Alkenes

An efficient approach to vicinal trifluoromethylthioamination of alkenes with a broad substrate scope catalyzed by electron-rich diaryl selenide has been developed. This intermolecular amination strategy was successfully applied to SCF3-esterification of alkenes using weak acids as nucleophiles.