A new cobalt/organophotoredox dual catalytic system is reported for the efficient retro‐hydroformylation of aldehydes. Under the optimized conditions, a wide range of α‐monosubstituted aldehydes are readily transformed into the desired alkenes in a one‐pot two‐step process, via the in situ formation of the corresponding 1,4‐dihydropyridines as key intermediates. This strategy represents a mild alternative to other traditional approaches requiring high temperatures and noble metal catalysts.

Trifluoromethylselenide dichlorides are rare selenium(IV) derivatives that have received limited attention despite their potential in organoselenium chemistry. We report a straightforward and efficient synthesis of dichloro(aryl)(trifluoromethyl)‐λ4‐selanes (ArSeCl2CF3) via chlorination of aryl trifluoromethylselenides in acetonitrile as the solvent of choice. After evaluating various chlorinating agents, sulfuryl chloride (SO2Cl2) revealed to be very efficient in a broad scope of substrates. Complementary density functional theory calculations provided mechanistic insight, indicating that chlorination proceeds via an asynchronous concerted mechanism with an accessible activation barrier and is exergonic, readily leading to the formation of Se(IV) fluorinated compounds. In contrast, the formation of the Se(VI) tetra‐chlorinated derivative via oxidative addition of Cl2 to the Se(IV) derivative was found to be both kinetically and thermodynamically infeasible.

We herein describe the synthesis of a pentafluoroethyl sulfoximine and its application in the pentafluoroethylation-difunctionalization of styrene derivatives. This sulfoximine reagent acts as a source of pentafluoroethyl radical to react with styrenes under mild photocatalytic conditions. By using simple nucleophiles, the pentafluoroethyl group can be introduced to styrenes with concomitant formation of C-O/C-N/C-S/C-C bonds, which significantly broadens the difunctionalization scope involving pentafluoroethylation compared to previous copper-based methods.

Herein, we report a metal-free divergent visible-light driven method for the synthesis of fluorinated sulfoximines. Both olefins and propellanes efficiently undergo difluorosulfoximination with yields up to 77% (65 examples). The process is general and robust and tolerates diverse functional groups, including esters, ethers, ketones, silyl groups, silyl ethers or boronic esters. The functionalization of diverse bioactive ingredients (8 examples) and various product manipulations demonstrate the synthetic usefulness of the developed synthetic platform. Finally, we rationalized the divergent reaction mechanism by performing Stern-Volmer quenching and EPR experiments that revealed the key activity of a difluoroalkyl sulfoximine radical.

A metal-free dual photo- and organocatalytic decarbonylation of aliphatic aldehydes is described for the first time. On the one hand, a wide range of tertiary aldehydes are smoothly decarbonylated thanks to the combination of thioxanthone as photocatalyst and diphenyl disulfide as organocatalyst. On the other hand, by simply using 4-CzIPN as photocatalyst instead of thioxanthone, various secondary aldehydes readily undergo decarbonylation in an orthogonal manner, via the in situ formation of 1,4-dihydropyridines. Both methodologies are compatible with various functional groups and are readily applied to the decarbonylation of complex molecules.

(Text in French) Alkoxy radicals: new opportunities for C–O bond formation Photoredox catalysis is a powerful tool which involves single electron transfer processes between a visible-light-activated photocatalyst and the substrates of the reaction. When N-alkoxypyridinium salts are used as reagents, these single electron transfers enable alkoxy radicals to be generated in a mild and controlled manner. This innovative method is being used to develop new alkoxylation reactions, enabling the synthesis of alpha-fluorinated ethers and ethers from simple substrates such as alkenes or enol ethers.

Hu's reagent is widely known for the electrophilic and radical difluoromethylation reactions of various compounds of interest for the pharmaceutical and agrochemical fields. Recently, our group described a cyclic version of this sulfoximine. In this article, the gram-scale synthesis of these two reagents, as well as a comparison of their reactivity in electrophilic and radical transformation, is disclosed. DSC and TGA measurements were carried out on the pure final compounds to assess the safety of the process.

α,β-Unsaturated carbonyl compounds are of significant biological and industrial importance, playing a key role in pharmaceutical chemistry, particularly in drug design. γ-Enolizable carbonyl compounds exhibit unique reactivity when undergoing functionalization at the remote γ-position. Despite notable advancements, γ-functionalization of these compounds still confronts considerable unresolved challenges. Radical chemistry has emerged as a powerful tool for constructing carbon–carbon and carbon–heteroatom bonds at the γ-position. In this review, we have summarized and categorized radical γ-functionalization methods developed over the past decades, focusing on substrates such as α,β-unsaturated amides, ketones, esters, and aldehydes.

Bicycloalkanes, cubanes and their structural analogues have emerged as bioisosteres of (hetero)arenes. To meet increasing demand, the chemical community has developed a plethora of novel synthetic methods. In this review, we assess the progress made in the field of light-driven construction and functionalization of such relevant molecules. We have focused on diverse structural targets, as well as on reaction processes giving access to: (i) [1.1.1]-bicyclopentanes (BCPs); (ii) [2.2.1]-bicyclohexanes (BCHs); (iii) [3.1.1]-bicycloheptanes (BCHeps); and (iv) cubanes; as well as other structurally related scaffolds. Finally, future perspectives dealing with the identification of novel reaction manifolds to access new functionalized bioisosteric units are discussed.

We present a metal-free photocatalytic approach for the synthesis of difluoroalkoxylatedketones. This strategy involves the generation of alkoxyl radicals from pyridinium salts upon the activity of a catalytic electron-donor-acceptor (EDA) complex. This mild process tolerates several functional groups and can be scaled up to gram scale. Diverse products manipulations accounts for the versatility of the obtained fluorinated products, highlighting the synthetic usefulness of this method. image

We report herein a general one‐pot perfluoroalkylation/dehydrohalogenation protocol for the selective perfluoroalkenylation of silyl dienol ethers in their γ position. Importantly, this methodology is applicable to the synthesis of a wide range of γ‐perfluoroalkenylated enals, enones and α,β‐unsaturated amides. Various perfluoroalkenyl moieties could be efficiently introduced, with an important impact on the E/Z diatereoselectivity of the newly formed fluorinated double bond.

We describe herein the direct electrophilic gamma-trifluoromethylthiolation and gamma-methylthiolation of enals, via the in situ formation of the corresponding silyl dienol ether. This one-pot process is carried out under simple and mild reaction conditions and is compatible with a variety of functional groups. In this article, the direct gamma-sulfenylation of enals is reported for the first time. Following this one-pot protocol, A wide variety of gamma-trifluoromethylthiolated and gamma-methylthiolated enals are readily prepared in up to 82 % yield with a full gamma selectivity. image

We describe the direct synthesis of gamma-fluoro enals from the corresponding silyl dienol ethers. This simple process operates under mild conditions and is compatible with a wide range of functionalities. The high gamma regioselectivity of this protocol was rationalized by means of theoretical calculations. The first general synthesis of gamma-fluoro alpha,beta-unsaturated aldehydes was achieved from the corresponding silyl dienol ethers and N-fluorobenzenesulfonimide (NFSI). The complete selectivity towards the gamma position was rationalized thanks to DFT calculations.image

We report herein recent advances made by our group and others in the field of oxygen-centered radicals generated under photo catalysis. Thanks to the design of new O-radical precursors, these radicals can now be efficiently trapped by unsaturated systems in an intermolecular manner, via the formation of a new C-O bond.

Access to original ortho thioether derivatives was achieved through a [3,3]-rearrangement in a one-pot two-step protocol. Several aryl-SCF3 compounds are reported by variation of the nitrile or of the trifluoroalkyl sulfoxide starting material. The variation of the perfluoroalkyl chain was also possible.

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. Flow chemistry provides an option for reaction scale-up further underscoring the synthetic usefulness of these methylation reagents. Mechanistic investigations suggest a single-electron transfer (SET) pathway induced by photoredox catalysis.

We report a general remote tribromo- and trichloromethylation process using CBr4 and CBrCl3 as ready available sources of trihalomethyl radicals. This method operates under mild and metal-free photocatalyzed conditions and enables the access to γ-trihalomethylated enals with complete regioselectivity in up to 71 % isolated yield. Importantly, this protocol is easily adapted to the selective one-pot synthesis of the corresponding γ-dihalomethylidenated enals in up to 49 % overall yield. Mechanistic studies are in favor of a radical chain propagation initiated by an oxidative quenching of the photocatalyst.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

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. The previously unknown perfluoroalkyl selenoximines family was also prepared with good yields. Having unlocked two strategies for the synthesis of fluoroalkylated SeIV and SeVI compounds, we then evaluated the Hansch-Leo lipophilicity parameters of these groups. Finally, asymmetric aryl perfluoroalkyl selenoximines were resolved to determine their absolute configurations.

Over the last years, methods devoted to the synthesis of asymmetric molecules bearing a perfluoroalkylated chain have been limited in number. Among them, only a few can be used on a large variety of scaffolds. This microreview aims at summarizing these recent advances in enantioselective perfluoroalkylation (-CF3, -CF2H, -CnF2n+1) and highlights the need for new enantioselective methods to easily synthesize chiral fluorinated molecules which would be useful for the pharmaceutical and agrochemical industries. Some perspectives are also mentioned.