Electricity-Driven Strain-Release Cascade Cyclization of Bicyclo[1.1.0]butane (BCB): Stereoselective Synthesis of Functionalized Spirocyclobutyl Oxindoles.

Spirocyclobutyl oxindoles, characterized by their unique three-dimensional structures, are valuable building blocks for many pharmacophores and drug units. However, stereoselective synthetic strategies for these scaffolds remain underdeveloped, with most existing methods relying on transition metal catalysts and stoichiometric redox reagents. In this work, we introduce an electrochemical strain-release driven cascade spirocyclization of bicyclo[1.

Formation to Transportation: En-Route Fission-Facilitated Formation of Spheres in a Phosphorus-Based Porous Organic Polymer for Transportation of Iodine.

Despite its potential as a clean power source to meet rising electricity demands, nuclear energy generates radioactive waste, including isotopes of iodine, that pose significant environmental and health risks. There is a growing demand to capture radioactive iodine and repurpose it effectively. However, achieving this dual functionality with a single material remains a significant challenge.

Manganese catalyzed chemo-selective synthesis of acyl cyclopentenes: a combined experimental and computational investigation.

Cyclopentenes serve as foundational structures in numerous natural products and pharmaceuticals. Consequently, the pursuit of innovative synthetic approaches to complement existing protocols is of paramount importance. In this context, we present a novel synthesis route for acyl cyclopentenes through a cascade reaction involving an acceptorless-dehydrogenative coupling of cyclopropyl methanol with methyl ketone, followed by a radical-initiated ring expansion rearrangement of the formed vinyl cyclopropenone intermediate.

Photocatalytic Decarboxylative Fluorination by Quinone-Based Isoreticular Covalent Organic Frameworks.

The strategic incorporation of fluorine atoms into molecules has become a cornerstone of modern pharmaceuticals, agrochemicals, and materials science. Herein, we have developed a covalent organic framework (COF)-based, robust photocatalyst that enables the photofluorodecarboxylation reaction of diverse carboxylic acids, producing alkyl fluorides with remarkable efficiency. The catalytic activity of an anthraquinone-based COF catalyst outperforms other structurally analogous β-ketoenamine COFs.

Substrate-controlled divergent remote C-H and N-H polyfluoroarylation of 2-aminopyrimidines with polyfluoroarenes Pd(II)/Pd(0) catalysis.

Substrate-controlled product divergence in the reaction of 2-aminopyrimidines with polyfluoroarenes under palladium catalysis is demonstrated for the first time. The reaction of secondary -alkylpyrimidine-2-amines with polyfluoroarenes leads to C5-H polyfluoroarylation C-H/C-H coupling, while secondary -aryl substituents yield N-H polyfluoroarylation, forming triarylamines.

Divergent Synthesis of Pyrazoles via Manganese Pincer Complex Catalyzed Acceptorless Dehydrogenative Coupling Reactions.

This report detailed the synthesis of multi-substituted pyrazoles through the acceptorless dehydrogenative coupling (ADC) reaction catalyzed by a well-defined manganese(I)-pincer complex. Symmetrically substituted pyrazoles were synthesized by reacting 1,3-diols with hydrazines. Unsymmetrically substituted pyrazoles were selectively made via the ADC of primary alcohols with methyl hydrazones.

Catalytic acceptorless dehydrogenative borylation of styrenes enabled by a molecularly defined manganese complex.

In this study, we employed a 3d metal complex as a catalyst to synthesize alkenyl boronate esters through the dehydrogenative coupling of styrenes and pinacolborane. The process generates hydrogen gas as the sole byproduct without requiring an acceptor, rendering it environmentally friendly and atom-efficient. This methodology demonstrated exceptional selectivity for dehydrogenative borylation over direct hydroboration.

DFT-Guided Mechanistic Insights into Chemodivergence: A Mixed Explicit-Implicit Solvent Description to Dictate the Chemoselectivity.

Herein we report a density functional theory (DFT)-guided mechanistic investigation of the nitrile reduction reaction, which exhibits a solvent-dependent chemodivergence. This study reveals an interesting mechanistic picture, highlighting the exact role of a protic solvent, isopropanol, in regulating the reaction outcome. The explicit solvent effect involving polar protic isopropanol favors imine metathesis by proton hopping through stepwise addition and elimination steps and thus produces a secondary amine as the final product.

Rejuvenation of dearomative cycloaddition reactions visible light energy transfer catalysis.

Dearomative cycloaddition is a powerful technique to access sp-rich three-dimensional structural motifs from simple flat, aromatic feedstock. The building-up of unprecedentedly diverse polycyclic scaffolds with increased saturation and stereochemical information having various applications ranging from pharmaceutical to material sciences, is an essential goal in organic chemistry. However, the requirement of large energy inputs to disrupt the aromaticity of an arene moiety necessitates harsh reaction conditions for ground state dearomative cycloaddition.

A π-conjugated covalent organic framework enables interlocked nickel/photoredox catalysis for light-harvesting cross-coupling reactions.

Covalent organic frameworks (COFs) are an outstanding platform for heterogeneous photocatalysis. Herein, we synthesized a pyrene-based two-dimensional C[double bond, length as m-dash]C linked π-conjugated COF Knoevenagel condensation and anchored Ni(ii)-centers through bipyridine moieties. Instead of traditional dual metallaphotoredox catalysis, the mono-metal decorated Ni@Bpy-spc-COF interlocked the catalysis mediated by light and the transition metal.

Asymmetric alkene-alkene reductive cross-coupling reaction visible-light photoredox/cobalt dual catalysis.

The first example of asymmetric alkene-alkene reductive coupling is demonstrated visible-light-fueled photoredox/cobalt dual catalysis. The desymmetrization reaction provided products (>20 examples) with up to five chiral centers in single-step operation in up to 95% yields with very high relative (>99 : 1 dr) and absolute stereochemistry (up to 98 : 2 er) control. The preliminary mechanistic investigations suggested that the critical mechanistic steps involved light-mediated controlled low-valent cobalt complex generation, oxidative ene-ene cyclization, and protonation.

Direct C(3)5-H Polyfluoroarylation of 2-Amino/alkoxy Pyridines Enabled by a Transient and Electron-deficient Palladium Intermediate.

Herein, we present an unprecedented azine-limited C5-H polyfluoroarylation of 2-aminopyridines enabled by a transient and electron-deficient perfluoroaryl-Pd species via C-H/C-H coupling. The protocol further allows C3(5)-H polyfluoroarylation of 2-alkoxypyridines guided by sterics and electronics for the first time. The late-stage C-H functionalization of drugs, drug derivatives, and natural product derivatives and synthesis of C5-aryl drug derivatives further demonstrated the method's utility.

Visiblelight-induced ternary electron donor-acceptor complex enabled synthesis of 2-(2-hydrazinyl) thiazole derivatives and the assessment of their antioxidant and antidiabetic therapeutic potential.

A mild and eco-friendly visible-light-induced synthesis of 2-(2-hydrazinyl) thiazole from readily accessible thiosemicarbazide, carbonyl, and phenacyl bromide in the absence of a metal catalyst and/or any extrinsic photosensitizer is reported. This approach only requires a source of visible light and a green solvent at room temperature to produce the medicinally privileged scaffolds of hydrazinyl-thiazole derivatives in good to outstanding yields. Experimental studies support the formation of a visible-light-absorbing, photosensitized colored ternary EDA complex.

Sustainable Synthesis of α-Hydroxycarboxylic Acids by Manganese Catalyzed Acceptorless Dehydrogenative Coupling of Ethylene Glycol and Primary Alcohols.

Herein, we report a straightforward synthesis of valuable α-hydroxycarboxylic acid molecules via an acceptorless dehydrogenative coupling of ethylene glycol and primary alcohols. A bench-stable manganese complex catalyzed the reaction, which is scalable, with the product being isolated with high yields and selectivities under mild conditions. The protocol is environmentally benign, producing water and hydrogen gas as the only byproducts.

Ruthenium-Catalyzed Reductive Coupling of Epoxides with Primary Alcohols via Hydrogen Transfer Catalysis.

Herein, we report the ruthenium-catalyzed synthesis of β-alkylated secondary alcohols via the regioselective ring-opening of epoxides with feedstock primary alcohols. The reaction utilized alcohol as the carbon source and the terminal reductant. Kinetic and labeling experiments elucidate the hydrogen transfer catalysis that operates via tandem Markovnikov selective transfer hydrogenation of terminal epoxides and hydrogen transfer-mediated cross-coupling of the resulting alcohol with primary alcohol substrates.

Intermolecular dearomative [4 + 2] cycloaddition of naphthalenes visible-light energy-transfer-catalysis.

The dearomative cycloaddition reaction serves as a blueprint for creating sp-rich three-dimensional molecular topology from flat-aromatic compounds. However, severe reactivity and selectivity issues make this process arduous. Herein, we describe visible-light energy-transfer catalysis for the intermolecular dearomative [4 + 2] cycloaddition reaction of feedstock naphthalene molecules with vinyl benzenes.

Dicarbofunctionalizations of an Unactivated Alkene via Photoredox/Nickel Dual Catalysis.

1,2-Dicarbofunctionalization of unactivated olefin has been reported under photoredox/nickel dual catalysis. The mildness of the visible-light-mediated reaction allows the use of various alkyl and aryl electrophiles with several sensitive functional groups. The protocol was equally applied for late-stage diversification of drugs and biologically active molecules.

Enantioselective C-H bond functionalization of aromatic ketones with 1,6-enynes photoredox/cobalt dual catalysis.

An enantioselective -C(sp)-H functionalization of ketones with 1,6-enynes is demonstrated photoredox/cobalt dual catalysis. The method exhibits high yields, functional group tolerance, and selectivity. Mechanistic studies suggested the operation of visible-light mediated low-valent cobalt complex generation, intramolecular cyclization, -C-H bond insertion, and reductive elimination as the key mechanistic steps.

Manganese-catalyzed hydrogenation, dehydrogenation, and hydroelementation reactions.

The emerging field of organometallic catalysis has shifted towards research on Earth-abundant transition metals due to their ready availability, economic advantage, and novel properties. In this case, manganese, the third most abundant transition-metal in the Earth's crust, has emerged as one of the leading competitors. Accordingly, a large number of molecularly-defined Mn-complexes has been synthesized and employed for hydrogenation, dehydrogenation, and hydroelementation reactions.

Dual Metalation in a Two-Dimensional Covalent Organic Framework for Photocatalytic C-N Cross-Coupling Reactions.

Covalent organic frameworks (COFs) are promising hosts in heterogeneous catalysis. Herein, we report a dual metalation strategy in a single two-dimensional-COF TpBpy for performing a variety of C-N cross-coupling reactions. [Ir(ppy)(CHCN)]PF [ppy = 2-phenylpyridine], containing two labile CHCN groups, and NiCl are used as iridium and nickel-metal precursors, respectively, for postsynthetic decoration of the TpBpy COF.

Photoredox/Nickel Dual Catalysis Enables the Synthesis of Alkyl Cyclopropanes via C(sp)-C(sp) Cross Electrophile Coupling of Unactivated Alkyl Electrophiles.

A facile synthesis of mono-, 1,1- and 1,2-disubstituted cyclopropanes via visible light-mediated photoredox/nickel dual catalysis is demonstrated. The challenging intramolecular C(sp)-C(sp) cross-electrophile coupling of readily available unactivated 1,3-dialkyl electrophiles was performed under mild conditions that allowed traditionally reactive functional groups to be included. Mechanistic inspection and control experiments revealed the importance of dual catalysis and that the reaction proceeds via a stepwise oxidative addition followed by an intramolecular S2 reaction.

Recent Development of Bis-Cyclometalated Chiral-at-Iridium and Rhodium Complexes for Asymmetric Catalysis.

The field of asymmetric catalysis has been developing to access synthetically efficacious chiral molecules from the last century. Although there are many sustainable ways to produce nonracemic molecules, simplified and unique methodologies are always appreciated. In the recent developments of asymmetric catalysis, chiral-at-metal Lewis acid catalysis has been recognized as an attractive strategy.

Cooperative Lewis Acid Catalysis for the Enantioselective C(sp)-H Bond Functionalizations of 2-Alkyl Azaarenes.

Herein, we describe the enantioselective C(sp)-H bond functionalizations of 2-alkyl azaarenes using a cooperative dual Lewis acid catalysis. An achiral Lewis acid activates the unactivated azaarene partner without the need for a strong base. Orthogonally, a chiral-at-metal Lewis acid catalyst enables LUMO lowering and induces chirality.

Advancements in multifunctional manganese complexes for catalytic hydrogen transfer reactions.

Catalytic hydrogen transfer reactions have enormous academic and industrial applications for the production of diverse molecular scaffolds. Over the past few decades, precious late transition-metal catalysts were employed for these reactions. The early transition metals have recently gained much attention due to their lower cost, less toxicity, and overall sustainability.

Nucleophilicities and Nucleofugalities of Thio- and Selenoethers.

Rate constants for the reactions of dialkyl chalcogenides with laser flash photolytically generated benzhydrylium ions have been measured photometrically to integrate them into the comprehensive benzhydrylium-based nucleophilicity scale. Combining these rate constants with the previously reported equilibrium constants for the same reactions provided the corresponding Marcus intrinsic barriers and made it possible to quantify the leaving group abilities (nucleofugalities) of dialkyl sulfides and dimethyl selenide. Due to the low intrinsic barriers, dialkyl chalcogenides are fairly strong nucleophiles (comparable to pyridine and N-methylimidazole) as well as good nucleofuges; this makes them useful group-transfer reagents.