Silver-Mediated Oxidative Aliphatic CH Trifluoromethylthiolation

C-H functionalisation of cycloalkanes

Among organic compounds hydrocarbons are inexpensive and possibly the most abundant among natural resources. Developing strategies for selective functionalisation of inert hydrocarbon C-H bonds is one of the most ideal synthetic paths that a synthetic chemist could think of. This critical review focuses on the recent development of various directed and non-directed cycloalkylations leading to the formation of carbon-carbon (C-C) and carbon-heteroatom (C-X) bonds. Apart from various transition metal catalysed cycloalkylations, this review also covers various metal-free cycloalkylation processes.

Selenide-catalyzed enantioselective synthesis of trifluoromethylthiolated tetrahydronaphthalenes by merging desymmetrization and trifluoromethylthiolation

Trifluoromethylthiolated molecules are an important class of biologically active compounds and potential drug candidates. Because of the lack of efficient synthetic methods, catalytic enantioselective construction of these molecules is rare and remains a challenge. To expand this field, we herein disclose a bifunctional selenide-catalyzed approach for the synthesis of various chiral trifluoromethylthiolated tetrahydronaphthalenes bearing an all-carbon quaternary stereocenter with gem-diaryl-tethered alkenes and alkynes by merging desymmetrization and trifluoromethylthiolation strategy. The products are obtained in high yields with excellent enantio- and diastereo-selectivities. This method can be applied to the desymmetrization and sulfenylation of diols as well. Computational studies reveal that selenide can activate the electrophilic reagent better than sulfide, confirming the higher efficiency of selenide catalysis in these reactions. On the basis of the theoretical calculations, an acid-derived anion-binding interaction is suggested to exist in the whole pathway and accounts for the observed high selectivities.

Catalytic enantioselective synthesis of trifluoromethylthiolated molecules remains a challenge. Here, the authors report a bifunctional selenide-catalyzed approach for the synthesis of structurally complex chiral trifluoromethylthiolated tetrahydronaphthalenes by merging desymmetrization and trifluoromethylthiolation.

Late stage trifluoromethylthiolation strategies for organic compounds

Substitution by the CF3S group allows for an increase in lipophilicity and electron-withdrawing properties along with an improvement in the bioavailability of medicinal targets; consequently, the late stage introduction of CF3S moieties into medicinal scaffolds is a sought-after strategy in synthetic organic chemistry. Different newly-developed electrophilic and nucleophilic reagents are used to effect the trifluoromethylthiolation of (hetero)aromatic compounds, aliphatic compounds (alkyl, alkenyl, alkynyl substrates), the trifluoromethylthiolation at the α- and β-carbonyl positions, and heteroatoms (N- and S-). Such reactions can involve homolytic substitutions, or functional-group substitutions (ipso). Addition reactions of electrophilic reagents to double and triple bonds followed by ring-cyclizations will be shown to yield relevant CF3S-substituted heteroaromatic compounds with relevant pharmacological action.

Catalyst and additive-free regioselective oxidative C–H thio/selenocyanation of arenes and heteroarenes with elemental sulfur/selenium and TMSCN

Elemental sulfur/selenium and TMSCN act as a novel combined thio/selenocyanation source for direct oxidative C–H thio/selenocyanation of (hetero)arenes under catalyst-free and additive-free conditions.

Copper-catalyzed direct trifluoromethylthiolation of indoles by tert-butyl 2-((trifluoromethyl)sulfonyl)hydrazine-1-carboxylate

A novel copper-catalyzed direct trifluoromethylthiolation of indoles and other electron-rich aromatics using tert-butyl 2-((trifluoromethyl)sulfonyl)hydrazine-1-carboxylate as the SCF₃ source was developed.

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.

Visible-light photocatalytic trifluoromethylthiolation of aryldiazonium salts: conversion of amino group into trifluoromethylthiol group

A visible-light photocatalytic trifluoromethylthiolation of aryl amine through in situ generation of aryldiazonium salts with S-trifluoromethyl 4-methoxylbenzenesulfonothioate was developed.

Nucleophilic trifluoromethylthiolation of bromoalkynones with AgSCF3: C(sp)–SCF3 bond formation towards ynonyl trifluoromethyl sulfides

C(sp)–SCF₃ bond formation via the AgSCF₃ mediated nucleophilic trifluoromethylthiolation of bromoalkynones, delivering various ynonyl trifluoromethyl sulfides in high yields.

Oxidation of Secondary Methyl Ethers to Ketones

We present a mild way of converting secondary methyl ethers into ketones using calcium hypochlorite in aqueous acetonitrile with acetic acid as activator. The reaction is compatible with various oxygen- and nitrogen-containing functional groups and afforded the corresponding ketones in up to 98% yield. The use of this methodology could expand the application of the methyl group as a useful protecting group.

China's flourishing synthetic organofluorine chemistry: innovations in the new millennium

The new millennium has witnessed the rapid development of synthetic organofluorine chemistry all over the world, and chemists in China have made significant contributions in this field. This review aims to provide a brief introduction to China's primary innovations from 2000 to early 2017, covering fluorination, fluoroalkylation, fluoromethylthiolation, fluoroolefination and polyfluoroarylation, as well as synthesis with fluorinated building blocks. Recent advances in the chemistry of difluorocarbene and the chemistry of carbon–fluorine bond activation are also discussed. As a conclusion, the review ends with some personal perspectives on the future development of China's synthetic organofluorine chemistry.

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.

Direct copper-catalyzed oxidative trifluoromethylthiolation of aryl boronic acids with AgSCF3

A copper-catalyzed direct oxidative trifluoromethylthiolation of aryl boronic acids with AgSCF₃ has been developed.

AgSCF3-mediated trifluoromethylthiolation of α,α-diaryl allylic alcohols via radical neophyl rearrangement

A novel example of AgSCF₃-mediated oxidative radical trifluoromethylthiolation of α,α-diaryl allylic alcohols is presented, producing various α-aryl-β-trifluoromethylthiolated carbonyl ketones via radical neophyl rearrangement under mild conditions.

DDQ-promoted direct C5-alkylation of oxazoles with alkylboronic acids via palladium-catalysed C–H bond activation

The first protocol for the direct C5-alkylation of oxazoles through transition-metal-catalysed C(5)–H bond activation.

Cp*CoIII-catalyzed directed C–H trifluoromethylthiolation of 2-phenylpyridines and 6-arylpurines

Cp*Co^III-catalyzed directed C–H trifluoromethylthiolation using N-trifluoromethylthiodibenzenesulfonimide as an electrophilic SCF₃ source is described.

A facile approach for the trifluoromethylthiolation of methylenecyclopropanes

Trifluoromethylthiolation of methylenecyclopropanes (MCPs) has been developed by using AgSCF₃/Na₂S₂O₈as a trifluoromethylthiolation source (SCF₃) to give trifluoromethylthiolated 1,2-dihydronaphthalene derivatives in moderate to good yields.

Oxidative decarboxylative radical trifluoromethylthiolation of alkyl carboxylic acids with silver(i) trifluoromethanethiolate and selectfluor

Practical, mild, and efficient. Broad scope and good functional group tolerance.

Visible-Light-Promoted Activation of Unactivated C(sp3)-H Bonds and Their Selective Trifluoromethylthiolation

Selective functionalization of ubiquitous C(sp³)-H bonds using visible light is a highly challenging yet desirable goal in organic synthesis. The development of such processes relies on both rational design and serendipitous discoveries from innovative tools such as screening technologies. Applying a mechanism-based screening strategy, we herein report photoredox-mediated hydrogen atom transfer catalysis for the selective activation of otherwise unactivated C(sp³)-H bonds, followed by their trifluoromethylthiolation, which has high potential as a late-stage functionalization tool. The generality of this method is exhibited through incorporation of the trifluoromethylthio group in a large number of C(sp³)-H bonds with high selectivity without the need for an excess of valuable substrate.

C-H Xanthylation: A Synthetic Platform for Alkane Functionalization

Intermolecular functionalizations of aliphatic C-H bonds offer unique strategies for the synthesis and late-stage derivatization of complex molecules, but the chemical space accessible remains limited. Herein, we report a transformation significantly expanding the chemotypes accessible via C-H functionalization. The C-H xanthylation proceeds in useful chemical yields with the substrate as the limiting reagent using blue LEDs and an easily prepared N-xanthylamide. The late-stage functionalizations of complex molecules occur with high levels of site selectivity, and a variety of common functionality is tolerated in the reaction. This approach capitalizes on the versatility of the xanthate functional group via both polar and radical manifolds to unlock a wide array of C-H transformations previously inaccessible in synthesis.