Cyclic Sulfoximines as Methyl and Perdeuteromethyl Transfer Agents and Their Applications in Photoredox Catalysis.

Benzo[1,3,2]dithiazole-1,1,3-trioxides are bench-stable and easy-to-use reagents. In photoredox catalysis, they generate methyl and perdeuteromethyl radicals which can add to a variety of radical acceptors, including olefins, acrylamides, quinoxalinones, isocyanides, enol silanes, and N-Ts acrylamide. As byproduct, a salt is formed which can be regenerated to the original methylating agent.

From perfluoroalkyl aryl sulfoxides to thioethers.

Access to original thioether derivatives was achieved through a [3,3]-rearrangement in a one-pot two-step protocol. Several aryl-SCF compounds are reported by variation of the nitrile or of the trifluoroalkyl sulfoxide starting material. The variation of the perfluoroalkyl chain was also possible.

Perfluoroalkyl Selenoxides, Selenones and Selenoximines: General Preparation and Properties.

A selective access to perfluoroalkyl selenoxides, via Oxone® as oxidant or to selenones by using a Polyoxometalate-based Ionic Liquid (POM-IL) as a catalyst for the oxidation step is described. The reaction works with various perfluoralkyl chains and substituents with satisfactory to excellent yields. A two-step one-pot reaction from selenocyanates was performed to gain access to perfluoroalkyl selenoxides.

Vinylic Trifluoromethylselenolation via Pd-Catalyzed C-H Activation.

Trifluorometylselenolation via C-H activation is barely described in literature. In particular, no such vinylic functionalization has been yet described. Herein, a palladium-catalyzed trifluoromethylselenolation of vinylic C-H bonds is described.

(Trifluoromethylselenyl)methylchalcogenyl as Emerging Fluorinated Groups: Synthesis under Photoredox Catalysis and Determination of the Lipophilicity.

The synthesis of molecules bearing (trifluoromethylselenyl)methylchalcogenyl groups is described via an efficient two-step strategy based on a metal-free photoredox catalyzed decarboxylative trifluoromethylselenolation with good yields up to 88 %, which raised to 98 % in flow chemistry conditions. The flow methods allowed also to scale up the reaction. The mechanism of this key reaction was studied.

Synthesis, Physical Properties and Application of a Series of New Polyoxometalate-Based Ionic Liquids.

This paper deals with the preparation and the characterization of four new ionic liquids resulting from the pairing of various polyoxotungstates or polyoxomolybdates with the cation trihexyltetradecylphosphonium. The physical properties measured by different techniques evidence that the viscosity and the rheological behaviors of such POM-based ionic liquids, POM-ILs, strongly depend on the nature of the POM, especially its charge. Playing on the nature of the POM, we can indeed obtain Newtonian liquids or some much more viscous materials exhibiting characteristics of resins or pseudo-plastics.

Controlled decomposition of SF by electrochemical reduction.

The electroreduction of SF is shown at ambient temperature in acetonitrile using an array of platinum microelectrodes to improve the electrical detection. Its half reduction potential occurs at -2.17 V vs Fc/Fc.

General, Practical and Selective Oxidation Protocol for CF₃S into CF₃S(O) Group.

A simple and efficient protocol for the oxidation of trifluoromethyl, mono- and difluoromethyl sulfides to the corresponding sulfoxides without over-oxidation to sulfones, using TFPAA prepared in situ from trifluoroacetic acid and 15% H₂O₂ aqueous solution was developed. The methodology is suitable for a wide range of aromatic and aliphatic substrates in milligram and multigram scales.

One-Pot Synthesis of Aryl- and Alkyl S-Perfluoroalkylated NH-Sulfoximines from Sulfides.

A general efficient one-pot synthesis of S-perfluoroalkylated NH-sulfoximines from sulfides has been developed using phenyliodine diacetate (PIDA) and ammonium carbamate. Remarkable rate enhancement with trifluoroethanol was observed, presumably due to H-bonding effects. These mild and metal-free conditions are compatible with -CH F, -CFCl , -CF H, -CF Br, -C F , and -CF groups, in both the alkyl- and aryl series.

Imidazolium-Based Ionic Liquids as Efficient Reagents for the C-O Bond Cleavage of Lignin.

The demethylation of lignin in ionic liquids (ILs) was investigated by using pure lignin model monomers and dimers together with dioxane-isolated lignins from poplar, miscanthus, and maize. Different methylimidazolium ILs were compared and the samples were treated with two different heating processes: microwave irradiation and conventional heating in a sealed tube. The conversion yield and influence of the treatment on the lignin structure were assessed by P NMR spectroscopy, size-exclusion chromatography, and thioacidolysis.

Fluoroalkyl Amino Reagents for the Introduction of the Fluoro(trifluoromethoxy)methyl Group onto Arenes and Heterocycles.

Fluoroalkyl amino reagents 1a and 2a have been developed from commercially available trifluoromethyl trifluorovinyl ether via a hydroamination reaction with diethylamine or dimethylamine. These reagents can be activated by treatment with a Lewis acid and subsequently used as a mono- or dielectrophile for the introduction of the fluoro(trifluoromethoxy)methyl group, either in Vilsmeier-type acylations of aromatic substrates or in the synthesis of fluorinated pyrazoles from CH-acidic substrates and of bis-fluorinated pyrazoles, all being important building blocks for medicinal and agricultural chemistry.

Dichlorotrifluoromethoxyacetic Acid: Preparation and Reactivity.

We describe the first gram scale preparation of the reagent dichlorotrifluoromethoxyacetic acid. This stable compound is obtained in five steps starting from the cheap diethylene glycol. The reactivity of the sodium salt of this fluorinated acid was also tested and allowed the preparation of new amides.

S-Trifluoromethyl Sulfoximine as a Directing Group in Ortho-Lithiation Reaction toward Structural Complexity.

The first use of the NH S-trifluoromethyl sulfoximine as an ortho directing group is described for the functionalization of the aryl group bonded to the sulfur atom. Various electrophiles (halogen, carbon, oxygen, sulfur, boron, etc.) are introduced on the aromatic ring.

First isolation of enantiopure perfluoroalkylated sulfilimines and sulfoximines.

Mono-, di- and trifluoromethyl sulfilimines and sulfoximines have been isolated for the first time in enantiopure form by separation of the racemate by supercritical fluid chromatography. The electrophilic trifluoromethylating Shibata reagent has been prepared as a single enantiomer.

Tuning the electrocatalytic hydrogen evolution reaction promoted by [Mo2O2S2]-based molybdenum cycles in aqueous medium.

We report the syntheses and characterizations, in the solid state and in solution, of three new cyclic polyoxothiomolybdates self-assembled around 2,5-dimethylterephthalate (DMT) and 2,5-bis(trifluoromethyl)terephthalate (DFMT) ligands, namely [Mo12DMT](2-), [Mo12DFMT](2-) and [Mo16DFMT](2-). A series of these two Mo12-compounds completed by the two Mo12-compounds obtained with 2,3,5,6-tetramethylterephthalate and trimesate ligands offer the opportunity to compare their electro-catalytic properties for reduction of protons into hydrogen. The ability of these compounds to promote the reduction of protons into hydrogen in aqueous medium is evidenced and the influence of the embedded ligand is highlighted, thus allowing proposal of a mechanism for the hydrogen evolution reaction catalyzed by these clusters.

Theoretical and experimental 1H, 13C and 15N NMR studies of N-alkylation of substituted tetrazolo[1,5-a]pyridines.

The (15)N as well as (1)H and (13)C chemical shifts of nine substituted tetrazolopyridines and their corresponding tetrazolopyridinium salts have been determined by using NMR spectroscopy at the natural abundance level of all nuclei in CD(3)CN. In this paper, we report, for the first time, the N-alkylation reaction of electron deficient tetrazolopyridines. The treatment of tetrazolopyridines 5-13 with one equivalent of trialkyloxonium tetrafluoroborate leads to a mixture of two isomers, i.

Asymmetric aza-Diels-Alder reaction of Danishefsky's diene with imines in a chiral reaction medium.

The asymmetric aza-Diels-Alder reaction of chiral imines with Danishefsky's diene in chiral ionic liquids provides the corresponding cycloadduct with moderate to high diastereoselectivity. The reaction has proved to perform better at room temperature in ionic liquids without either Lewis acid catalyst or organic solvent. Chiral ionic liquids are recycled while their efficiency is preserved.