Silver-Mediated anti-Markovnikov and Markovnikov-Selective Hydrotrifluoromethylthiolation of Terminal Alkynes

A HMPA-H2O mediated oxygenative carbocyclization of 2-alkynylphenyl-substituted p-quinone methides to indenones

Herein, we report a transition-metal and base-free protocol to access a wide range of functionalized indenone derivatives through a HMPA-H2O-mediated oxygenative annulation of 2-alkynylphenyl-substituted p-quinone methides. This method worked effectively for most of the p-QMs investigated and the corresponding indenone derivatives were obtained in moderate to good yields. This methodology was further extended to the formal synthesis of one of the resveratrol based natural products, (±)-isopaucifloral F.

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

K2S2O8-Mediated Synthesis of Highly Functionalized Pyrroles via Oxidative Self-Dimerization of N-Propargylamines

An efficient methodology has been developed for the synthesis of tetra- and pentasubstituted pyrroles via oxidative self-dimerization of N-propargylamines catalyzed by silver benzoate in the presence of K₂S₂O₈ in good yields. The protocol provides a simple route for the synthesis of both tetra- and pentasubstituted pyrroles with two carbonyl groups in the side chain. The methodology can be extended toward the synthesis of pyrrolo[3,4-d]pyridazine.

Photocatalyzed Radical Relayed Regio- and Stereoselective Trifluoromethylthiolation-Boration

Vinylboronates and alkylboronates are key components in variegated transformations in all aspects of chemical science. This work describes a sequential radical difunctionalization strategy for the construction of fluorine-containing vinylboronates and alkylboronates with the integrated redox-active reagent N-trifluoromethylthiophthalimide. This multifunctional N-S precursor offers a scalable and practical protocol for the trifluoromethylthiolation-borylation of unsaturated hydrocarbons in a highly regio- and stereoselective fashion, which can be further converted into valuable synthons via boryl migration.

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.

Regio- and Stereoselective Thianthrenation of Olefins To Access Versatile Alkenyl Electrophiles

Herein, we report a regioselective alkenyl electrophile synthesis from unactivated olefins that is based on a direct and regioselective C-H thianthrenation reaction. The selectivity is proposed to arise from an unusual inverse-electron-demand hetero-Diels-Alder reaction. The alkenyl sulfonium salts can serve as electrophiles in palladium- and ruthenium-catalyzed cross-coupling reactions to make alkenyl C-C, C-Cl, C-Br, and C-SCF3 bonds with stereoretention.

Practical and regioselective halo-trifluoromethylthiolation of sulfur ylides

A H2O mediated practical and highly regioselective chloro- and bromo-trifluoromethylthiolation of sulfur ylides is reported using a difunctionalization strategy. In the reaction sequence, sulfur ylides presumably react with an electrophilic trifluoromethylthiolating reagent to generate an α-SCF3 substituted sulfonium salt intermediate, which then undergoes a substitution with nucleophilic halogens.

Visible-light-induced radical trifluoromethylthiolation of N-(o-cyanobiaryl)acrylamides

An efficient and general visible-light-mediated trifluoromethylthiolation of N-(o-cyanobiaryl)acrylamides has been successfully accomplished using N-trifluoromethylthiosaccharin as an effective source of SCF3 radicals. The reaction was proposed to proceed via a domino radical trifluoromethylthiolation/cyano insertion/cyclization to afford the corresponding SCF3-containing ring-fused phenanthridine derivatives in moderate to good yields.

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.

Cyanotrifluoromethylthiolation of unactivated dialkyl-substituted alkynes via cyano migration: synthesis of trifluoromethylthiolated acrylonitriles

Herein a novel, elusive cyanotrifluoromethylthiolation of unactivated dialkyl-substituted alkynes by means of intramolecular distal cyano migration is reported.

Catalyst-free synthesis of α-thioacrylic acids via cascade thiolation and 1,4-aryl migration of aryl alkynoates at room temperature

A simple and facile catalyst-free strategy has been developed for the synthesis of α-thioacrylic acids from readily-available aryl alkynoates and thiols at room temperature under air.

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.

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.

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.