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

Electrochemical Trifluoromethylthiolation/Cyclization of N-Arylacrylamides with AgSCF3: Access to SCF3-Containing Oxindoles

An environmentally friendly electrochemical strategy for the synthesis of SCF3-containing oxindoles was developed. This electrochemical transformation was accomplished through a cascade trifluoromethylthiolation/cyclization of N-acrylamides with AgSCF3, obviating the requirement for external oxidants. A variety of functional groups were well tolerated in this transformation.

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.

Cascade Oxidative Trifluoromethylthiolation and Cyclization of 3-Alkyl-1-(2-(alkynyl)phenyl)indoles

Persulfate-promoted radical cascade trifluoromethylthiolation and cyclization of 3-alkyl-1-(2-(alkynyl)phenyl)indoles with AgSCF₃ were investigated. This protocol provides a novel route to CF₃S-substituted indolo[1,2-a]quinoline-7-carbaldehydes and CF₃S-substituted indolo[1,2-a]quinoline-7-methanone derivatives via the formation of the C-SCF₃ bond and C-C bond and benzylic carbon oxidation in a single step. This reaction can accommodate a broad range of functional groups. The single-crystal X-ray diffraction data confirm the chemical structure of the product. A scale-up experiment and radical inhibition experiments were operated in the reaction system. Photophysical properties of some selected 5-((trifluoromethyl)thio)indolo[1,2-a]quinoline-7-carbaldehydes were studied by UV-visible and fluorescence spectroscopy.

Copper-assisted trifluoromethylthiolation/radical cascade cyclization of alkynes to construct SCF3-containing dioxodibenzothiazepines

A mild and efficient Cu-assisted trifluoromethylthiolation/radical cascade cyclization of alkynes with readily available and stable AgSCF₃ as the trifluoromethylthiolating reagent has been disclosed. This transformation provides an opportunity to construct a series of potential medicinally valuable trifluoromethylthio-substituted dioxodibenzothiazepines with wide functional group compatibility. This protocol opens up a new avenue for the construction of useful trifluoromethylthiolated seven-membered N-heterocycles.

Free Radical Promoted Trifluoromethylthiolation of Alkynes to Access SCF3-Containing Dibenzazepines or Dioxodibenzothiazepines

Persulfate-promoted radical cascade trifluoromethylthiolation of aryl acetylenes with AgSCF₃ provides a simple reaction system for the synthesis of SCF₃-substituted dibenzazepines or dioxodibenzothiazepines with good Z/E selectivity. The single-crystal X-ray diffraction data confirms the structures of the final products. A series of scaled-up experiments, further transformations, and radical inhibition experiments were operated in the reaction system.

Three-Component Friedel-Crafts Transformations: Synthesis of Alkyl and Alkenyl Trifluoromethyl Sulfides and Alkenyl Iodides

Straightforward and mild hexafluoroisopropanol (HFIP)-mediated, metal-free, three-component Friedel-Crafts approaches are reported for the synthesis of alkenyl and alkyl trifluoromethyl sulfides from arenes, (PhSO₂)₂NSCF₃, and alkynes or alkenes, respectively. The transformations proceed with high regio- and stereochemical control via the initial formation of cationic thiirenium and thiiranium intermediates, respectively, followed by Friedel-Crafts reactions with the arene. A mechanistically related three-component synthesis of alkenyl iodides from arenes, alkenes, and N-iodosuccinimide is also reported.

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

The Co(ii)/spiroBox-catalyzed enantioselective Mukaiyama-Mannich reaction for the synthesis of quaternary α-amino acid derivatives

Co(ii)/spiroBox-catalyzed Mukaiyama-Mannich reactions of enol silyl ethers with cyclic N-sulfonyl ketimino esters were examined and showed excellent yields and enantioselectivity values.

Electrochemical Trifluoromethylthiolation and Spirocyclization of Alkynes with AgSCF3: Access to SCF3-Containing Spiro[5,5]trienones

A novel and efficient strategy for trifluoromethylthiolation and dearomatization of activated alkynes with stable and readily available AgSCF₃ has been developed. Reported herein is the unprecedented electrochemical generation of the SCF₃ radical in the absence of persulfate for the synthesis of SCF₃-containing spiro[5,5]trienones in good yields via a 6-exo-trig radical cyclization.

Synthetic developments on the preparation of sulfides from thiol-free reagents

This critical review covers the main thiolating reagents with respect to their characteristics and reactivities. In fact, they are complementary to each other and bring different thiolation strategies, avoiding the hazardous thiol derivatives.

Denitrative Cross-Couplings of Nitrostyrenes

Interestingly, β-nitrostyrenes, typically bench stable compounds, are highly promising cross-coupling partners, due to their excellent availability and well understood reactivity. In this review, we report on the discovery and advancements, in the field of stereoselective, denitrative cross-couplings of β-nitrostyrenes with miscellaneous organic reagents. The rapidly expanding field offers alternative access to a broad range of functionalized alkenes, including β-alkylated styrenes, chalcones, stilbenes, cinnamic acids, and conjugated sulfones and phosphonates. The most important mechanistic pathways are briefly discussed, to familiarize readers with the elementary reactions occurring during the coupling.