Nickelaelectro-Catalyzed C─H Activation to β-Arylated Pyrroles via Multiple Dehydrogenation.

Nickel electrocatalysis has emerged as a powerful strategy for sustainable C─H activation, offering an environmentally benign alternative to traditional methods based on stoichiometric oxidants. We, herein, report a nickela-electrocatalyzed approach for the expedient synthesis of β-arylated pyrroles via a unique multiple dehydrogenative C─H activation approach. Hence, direct C─C bond formation between pyrroles and arenes was enabled, obviating the need for prefunctionalized substrates.

-Selective Iron-Catalyzed C-H Alkylations with Allenes: Access to Stereodefined Olefins.

We report an unprecedented iron-catalyzed C-H alkylation of widespread benzamides using readily available allenes. The method, based on cheap, nontoxic, and earth abundant iron catalysts, exploits the assistance of removable triazole directing groups to yield a wide array of internal olefins, even at room temperature, with excellent stereocontrol, good yields, and broad functional group tolerance.

Stereocontrolled Construction of Multi-Chiral [2.2]Paracyclophanes via Cobaltaphotoredox Dual Catalysis.

-/-disubstituted multichiral [2.2]-paracyclophanes (PCPs) represent privileged scaffolds for asymmetric catalysis, finding extensive applications as chiral ligands in organic synthesis and functional materials. However, enantioselective C-H activation strategies for accessing these structurally demanding molecules remain largely underexplored.

Electroreductive room-temperature C-H activations with RuCl·HO precatalyst cathodic ruthenium(iii/ii) manifold.

We, herein, disclose a strategy to directly utilize user-friendly RuCl·HO for - as well as -C-H functionalizations at low temperatures. The key to success was the formation of the active ruthenium catalyst through cathodic electron transfer, setting the stage for C-H activations under exceedingly mild reaction conditions. The robustness of our electrocatalysis process was highlighted by the late-stage diversification of compounds of relevance to chemical, agrochemical, and pharmaceutical industries, as well as simple amines as terminal reductants for the electroreduction.

Photoinduced Ruthenium-Catalyzed -C-H Glycosylation.

C-H functionalization has surfaced as a powerful tool in molecular synthesis. -Selective arene C-H activations typically rely on rather costly palladium or rhodium catalysts, elaborate template auxiliaries, or elevated temperatures, and -glycosylations are scarce. In contrast, we herein report on a visible-light-induced ruthenium-catalyzed -C-H glycosylation that utilizes a stable ruthenium-(II) catalyst under exceedingly mild conditions at room temperature.

Electrochemical Access to Functionalized Benzofurans via Versatile Radical-Polar Crossover Carbo-Cyclizations.

Highly functionalized benzofurans represent omnipresent biorelevant compounds of practical importance in the pharmaceutical industry and material sciences. Electrochemistry provides a platform for enabling redox-neutral transformations via single-electron transfer (SET), analogous to visible-light photocatalysis, while eliminating the need for costly photocatalysts and offering inherent tunability through adjustable redox potentials. Herein, we report a radical-polar crossover for isohypsic electrosynthesis to access functionalized benzofurans in a resource-economical manner.

Difunctionalization of bicyclo[1.1.0]butanes enabled by merging C-C cleavage and ruthenium-catalysed remote C-H activation.

The high fraction of -hybridized carbon atom (F ) character of cyclobutane derivatives renders them as highly promising bioisosteres for otherwise typically flat arenes. Here, to address the current needs in medicinal chemistry for F -rich molecules, we disclose a distinct strategy that exploits the merger of C-C scission in bicyclo[1.1.

Electrochemical Commodity Polymer Up- and Re-Cycling: Toward Sustainable and Circular Plastic Treatment.

The demand for commodity plastics reaches unprecedented dimensions. In contrast to the well-developed plethora of methods for polymer synthesis, sustainable strategies for the end-of-life management of plastics continue to be scarce. While mechanical re-cycling often results in downgraded materials, chemical re-cycling or up-cycling offers tremendous potential for an efficient and green approach, thereby addressing the precarious treatment of post-use plastics within a circular carbon economy.

A unified approach to -selective methylation, mono-, di- and trifluoromethylation of arenes.

Matched molecular series (MMS) are series of molecules that differ only by a single modification at a specific site. The synthesis of MMS is a desirable strategy in drug discovery campaigns. Small aliphatic motifs, notably methyl, mono-, di- and trifluoromethyl substituents (C units), are known to have profound effects on the physiochemical properties and/or potency of drug candidates.

Photoelectrochemical Iron(III) Catalysis for Late-Stage C─H Fluoroalkylations.

Chemo- and site-selective functionalization of complex molecules poses a fundamental challenge. Herein, we introduce a resource-economic photoelectrocatalysis strategy to enable versatile direct fluoroalkylations catalyzed by Earth-abundant iron and paired with the hydrogen evolution reaction (HER). Notably, the devised approach proved amenable to versatile late-stage C─H fluoroalkylations of bio-relevant heterocycles, such as xanthines, nucleobases, and nucleosides.

Highly-Selective Electrochemical Decarboxylative Late-Stage Functionalization of Amino Acids.

A unified electrochemical decarboxylative strategy for the site-selective construction of carbon-heteroatom bonds is disclosed herein. The metal- and catalyst-free decarboxylation provides access to the functionalization of C- and N-terminus from the simple amino acid feedstock. A wide variety of primary, secondary, and tertiary acids or alcohols were well tolerated.

Parametrization of κ-,-Oxazoline Preligands for Enantioselective Cobaltaelectro-Catalyzed C-H Activations.

Enantioselective electrocatalyzed C-H activations have emerged as a transformative platform for the assembly of value-added chiral organic molecules. Despite the recent progress, the construction of multiple C(sp)-stereogenic centers via a C(sp)-C(sp) bond formation has thus far proven to be elusive. In contrast, we herein report an annulative C-H activation strategy, generating chiral Fsp-rich molecules with high levels of diastereo- and enantioselectivity.

Three-Coordinate Iron(0) Complex-Catalyzed Regioselective C-H Alkylation of Indole Derivatives.

The synthesis of alkylated indoles, which are key intermediates for various drugs and bioactive molecules, is of great importance. However, most reports on the synthesis of functionalized indoles use toxic and expensive 4d or 5d metal catalysts, limiting the further application of these methods. Herein, we disclose a versatile regioselective C-H alkylation of indole derivatives using a well-defined three-coordinate iron(0) complex.

Ruthenaelectro-catalyzed C-H phosphorylation: to position-selectivity switch.

The position-selective C-H bond activation of arenes has long been a challenging topic. Herein, we report an expedient ruthenium-electrocatalyzed site-selective -C-H phosphorylation of arenes driven by electrochemical hydrogen evolution reaction (HER), avoiding stoichiometric amounts of chemical redox-waste products. This strategy paved the way to achieve unprecedented ruthenaelectro-catalyzed -C-H phosphorylation with excellent levels of site-selectivity.

Visible light-induced ruthenium(ii)-catalyzed hydroarylation of unactivated olefins.

Hydroarylation reactions have emerged as a valuable tool for the direct functionalization of C-H bonds with ideal atom economy. However, common catalytic variants for these transformations largely require harsh reaction conditions, which often translate into reduced selectivites. In contrast, we herein report on a photo-induced hydroarylation of unactivated olefins at room temperature employing a readily available ruthenium(ii) catalyst.

Metallaelectro-catalyzed alkyne annulations C-H activations for sustainable heterocycle syntheses.

Alkyne annulation represents a versatile and powerful strategy for the assembly of structurally complex compounds. Recent advances successfully enabled electrocatalytic alkyne annulations, significantly expanding the potential applications of this promising technique towards sustainable synthesis. The metallaelectro-catalyzed C-H activation/annulation stands out as a highly efficient approach that leverages electricity, combining the benefits of electrosynthesis with the power of transition-metal catalyzed C-H activation.

Copper(0)-Catalyzed Reductive Coupling of Disulfurating Reagents and (Hetero)aryl/Alkyl Halides.

Herein, we reported a copper(0)-catalyzed reductive coupling of disulfurating reagents and (hetero)aryl/alkyl halides. Copper(0) can be directly inserted into tetrasulfide and then undergoes reductive coupling with (hetero)aryl Iodides to construct disulfide. The method features the unprecedented use of copper(0)-catalyzed disulfurating reagents (tetrasulfides) in cross-coupling chemistry and is convenient with broad substrate scopes, even applicable to different halogenated hydrocarbons.

Ruthenium(II)-Catalyzed Remote C-H Alkylation of Arenes Using Diverse N-Directing Groups through Aziridine Ring Opening.

An efficient approach for the remote C-H alkylation of arenes, employing a variety of N-directing groups is described. This method facilitates the straightforward synthesis of valuable phenylethylamine derivatives by exclusively cleaving the benzylic C-N bond in aziridines. Furthermore, these products can easily remove the protecting groups, resulting in a variety of meta-substituted compounds, such as amines and ketones, which hold significance in synthetic chemistry.

Enantioselective Cobaltaphotoredox-Catalyzed C-H Activation.

The quest for sustainable strategies in molecular synthesis has spurred the emergence of photocatalysis as a particularly powerful technique. In recent years, the application of photocatalysis in this context has greatly promoted the development of asymmetric catalysis. Despite the impressive advances, enantioselective photoinduced strong arene C-H activations by cobalt catalysis remain unexplored.

Electrochemical Glycosylation via Halogen-Atom-Transfer for -Glycoside Assembly.

Glycosyl donor activation emerged as an enabling technology for anomeric functionalization, but aimed primarily at -glycosylation. In contrast, we herein disclose mechanistically distinct electrochemical glycosyl bromide donor activations via halogen-atom transfer and anomeric -glycosylation. The anomeric radical addition to alkenes led to -alkyl glycoside synthesis under precious metal-free reaction conditions from readily available glycosyl bromides.

Photoelectrocatalytic [4+2] Annulation for S-Heterocycle Assembly Enabled by Proton-Coupled Electron Transfer (PCET).

Cross-dehydrogenative couplings (CDC) present an efficient strategy for the assembly of biorelevant heterocycles, but are thus far largely limited to toxic transition metals and rather harsh reaction conditions. In sharp contrast, we, herein report on a mild photoelectrocatalyzed CDC-[4+2] annulation enabling the synthesis of functionalized isothiochromenes enabled by a proton-coupled electron transfer (PCET) strategy. The transformative photoelectrocatalysis obviated toxic transition-metal, high reaction temperatures, and stoichiometric chemical redox reagents.

C-S-Selective Stille-Coupling Enables Stereodefined Alkene Synthesis.

A palladium-catalyzed highly C-S-selective Stille cross-coupling between aryl thianthrenium salts and tri- or tetrasubstituted alkenyl stannanes is described. Herein, critical challenges including site- and chemoselectivity control are well addressed through C-H thianthrenation and C-S alkenylation, thereby providing an expedient access to stereodefined tri- and tetrasubstituted alkenes in a stereoretentive fashion. Indeed, the palladium-catalyzed Stille-alkenylation of poly(pseudo)halogenated arenes displays privileged capability to differentiate C-S over C-I, C-Br, C-Cl bonds, as well as oxygen-based triflates (C-OTf), tosylates (C-OTs), carbamates and sulfamates under mild reaction conditions.

Well-Defined Highly-Coordinated Copper(III) Iodide and Pincer Tris(trifluoromethyl)copper Complexes.

Copper(III) iodide and bromide complexes representing a unique combination of highly-coordinated metal and soft polarizable anions were synthesized and fully characterized, including X-ray crystallography. Ligand substitution in well-defined highly-coordinated copper complex PyCu(CF) with pincer ligands was achieved to give formally octahedral copper(III) complexes.