A switch strategy for the synthesis of C4-ethylamine indole and C7-aminoindoline via controllable carbon elimination.

Controllable ß-carbon elimination to extrude norbornene remains a long-standing challenge in palladium and norbornene chemistry. Herein, this manuscript describes a switchable synthesis of biologically active C4-ethylaminoindole and C7-aminoindoline scaffolds by controlling ß-carbon elimination, utilizing aziridine as a C-H ethylamination reagent through a C-N bond cleavage reaction. Furthermore, the protecting groups of the product can be easily removed, offering an unusual method for the synthesis of dopamine receptor agonists.

Nickel-Catalyzed Narasaka-Heck Cyclization Carbonylation of Unsaturated Oxime Esters with Arylboronic Acids.

The Narasaka-Heck reaction is one of the most straightforward methods for constructing pyrroline derivatives. Herein, we report a novel nickel-catalyzed three-component carbonylation reaction, which cleverly realizes the continuous construction of C(sp3)-N bonds and C(sp3)-C(sp2) bonds and effectively promotes the synthesis of acyl-substituted pyrroline derivatives. Furthermore, this strategy not only expands the conversion pathway of γ,δ-unsaturated oxime esters but also provides a new method for the synthesis of nitrogen-containing heterocyclic compounds.

Selective Synthesis of Mono- and Bis-Phosphorylated (Dihydro)pyrans via TMSCl-Mediated Cascade Phosphorylation Cycloisomerization of Enynones.

A chlorotrimethylsilane (TMSCl)-mediated cascade phosphorylation and cycloisomerization of enynones with diphenylphosphine oxides is presented. This methodology enables the highly selective synthesis of monophosphorylated 2H-pyrans and bisphosphorylated dihydropyrans through precise solvent-reagent stoichiometry control. The strategy demonstrated excellent functional group compatibility and high yields (up to 96%), providing facile access to structurally diverse phosphorylated heterocycles with potential applications in medicinal chemistry and materials science.

Palladium-Catalyzed Four-Component Radical Cascade Carbonylation Access to 2,3-Disubstituted Benzofuran Derivatives.

Multicomponent radical tandem reactions have emerged as a crucial technique for synthesizing complex molecules in organic chemistry. In this study, we report a palladium-catalyzed four-component difluoroalkylative carbonylation of enynes and ethyl difluoroiodoacetate. This transformation proceeds through a multistep sequential reaction that introduces reactive difluoro and carbonyl groups while constructing the benzofuran skeleton. Moreover, a variety of valuable 2,3-disubstituted benzofuran derivatives were obtained in respectable yields with excellent functional group compatibility.

Synthesis of 1,2,4-diazaphospholes via base-promoted cyclization reaction of hydrazonoyl chlorides and [Bu4N][P(SiCl3)2].

Aromatic 1,2,4-diazaphospholes featuring distinct hybrid-mode nitrogen atoms (N(λ3σ2), N(λ3σ3)) and low-valent phosphorus atoms (λ3σ2) exhibited the characteristic of serving as unique hybrid ligands. This study presented a one-pot reaction involving the base-promoted stepwise cyclization of hydrazonoyl chlorides and [Bu4N][P(SiCl3)2] to yield 1,2,4-diazaphospholes, providing an effective method for synthesizing such compounds.

Fluoride-Mediated Aryne 1,2-Difunctionalization Involving C═S Bond Heterolysis.

We have successfully synthesized a series of bidentate ligands by utilizing 2-(trimethylsilyl)phenyl trifluorosulfonate as a precursor for the benzyl group. This method proceeded by inserting a polythiourea into the C═S π-bond, intramolecular ring proton migration, and ring opening. Salient features of this strategy are mild reaction conditions, a novel product structure, excellent stereochemistry, and a good functional group tolerance. Furthermore, a series of density functional theory calculations were performed to gain insights into the transfer mechanism.

Direct Synthesis of C4-Acyl Indoles via C-H Acylation.

The direct synthesis of C4-acyl indoles deprived of C2 and C3 substituents has proven to be challenging, with scarce efficient synthetic routes being reported. Herein, we disclose a highly site-selective palladium-catalyzed C-H acylation for the construction of C4-acyl indoles via a Catellani-Lautens cyclization strategy. In addition, we systematically studied the ortho C-H acylation mechanism of iodoaniline through density functional theory (DFT) calculations and combined experimental results to elucidate the principle of high chemoselectivity brought by triazine benzoate as an acylation reagent.

Palladium-Catalyzed Three-Component Cascade Carbonylation Reaction to Construct Benzofuran Derivatives.

A novel three-component cyclization carbonylation reaction of iodoarene-tethered propargyl ethers with amine and CO is reported. This palladium-catalyzed cascade reaction undergoes a sequence of oxidative addition, unsaturated bond migration, carbonyl insertion, and nucleophilic attack to deliver the benzofuran skeleton. Both aromatic amines and aliphatic amines could proceed smoothly in this transformation under one atm of CO.

Interaction between hydroxymethanesulfonic acid and several organic compounds and its atmospheric significance.

The interactions of the micro-mechanism of hydroxymethanesulfonic acid (HMSA) with the typical small organic molecule in atmospheric (X = methanol, formaldehyde, formic acid, methyl formate, dimethyl ether, acetone) has been investigated by density functional theory (DFT), quantum theory of atoms in molecules (QTAIM), Generalized Kohn-Sham Enery Decomposition Analysis (GKS-EDA) and the atmospheric clusters dynamic code (ACDC). The results of DFT show that the stable six- to eight-membered ring structures are easily formed in HMSA-X clusters. According to the topological analysis results of the AIM theory and the IRI method, a strong hydrogen bonding interaction is present in the complex. GKS-EDA results show that electrostatic energy is the main contributor to the interaction energy as it accounts for 51 %-55 % of the total attraction energy. The evaporation rates of HMSA-HMSA and HMSA-HCOOH clusters were much lower than those of the other HMSA complexes. In addition, the Gibbs energy of formation (ΔG) of HMSA-X dimers is investigated under atmosphere temperature T = 217-298 K and p = 0.19-1.0 atm, the ΔG decreased with decreasing of the atmosphere temperature and increased with the decrease of atmospheric pressure, indicating that the low temperature and high pressure may significantly facilitate to the formation of dimers.

Hydrazone Phosphaketene as a Synthetic Platform To Obtain Three Classes of 1,2,4-Diazaphosphol Derivatives by Switchable Chemoselectivity Strategies.

We introduce switchable chemoselectivity strategies based on the hydrazone phosphaketene intermediate to synthesize three classes of 1,2,4-diazaphosphol derivatives. First, the five-membered heterocyclic P and O anion intermediates acted as nucleophilic agents in the selective construction of C-P and C-O bonds. Second, the phosphinidene served as a phosphorus synthon, allowing for the formation of C-P and C-N bonds. Finally, a stepwise mechanism, supported by DFT calculations, was invoked to explain the reaction selectivity.

Template Synthesis to Solve the Unreachable Ortho C-H Functionalization Reaction of Aryl Iodide.

This report describes the use of a simple Pd/NBE catalytic system to achieve ortho C-H oxylation and phosphonylation and other functionalizations of aryl iodide through templated conversion reactions. Dimethylamine is introduced in the ortho-site of aryl iodide through C-H amination, and aryl dimethylamine is quickly converted to methyl quaternary ammonium salt precipitation. Methyl quaternary ammonium salt avoids Hofmann elimination in subsequent functionalization. This method solves various ortho functionalization reactions of aryl iodide that have not been achieved for a long time in the field of Pd/NBE chemistry indirectly.

Synthesis of 3(2H)-furanone derivatives: p-TsOH/halotrimethylsilane promoted cycloketonization of γ-hydroxyl ynones.

A p-TsOH/halotrimethylsilane facilitated cycloketonization of γ-hydroxyl ynones is detailed. This methodology enables the one-step synthesis of polysubstituted 3(2H)-furanone products. It is remarkable that the reaction exhibits excellent regio- and chemoselectivity by the addition of very small quantities of p-toluenesulfonic acid and water.

Regioselective C-H Active Carbonylation via 1,4-Palladium Migration.

We report a highly regioselective three-component coupling reaction of styrene, CO gas, and an amine compound to synthesize multisubstituted α,ß-unsaturated amides, which involves a palladium-catalyzed sequential 1,4-palladium migration, C(sp2)-H activation, carbonylation, and amination. Salient features of this strategy include the use of 1 atm of CO, excellent stereochemistry, and good functional group tolerance. Further, a series of control experiments and density functional theory calculations were performed to afford some insights for the transfer mechanism.

Redox Neutral Radical-Relay Nickel-Catalyzed Remote Carbonylation.

A novel and efficient method for the catalytic installation of a carbonyl group via remote radical coupling is disclosed. The nickel-catalyzed reaction proceeds to undergo a sequential single-electron transfer, 1,5-hydrogen atom transfer, and carbonyl insertion, thus providing the α-substituted ketone. Further, this reaction could be carried out smoothly under normal pressure and redox-neutral conditions, and demonstrated functional-group compatibility and excellent site-selectivity.

Direct synthesis of phosphorotrithioates from [TBA][P(SiCl3)2] and disulfides.

Sulfur-containing organophosphorus molecules have played a pivotal role in organic synthesis, pharmaceutical pesticides and functional materials, thereby motivating researchers worldwide to establish S-P bonds from more environmentally friendly phosphorus sources. In this study, a novel method was developed for constructing S-P bonds, specifically by reacting the inorganic phosphorus derivative TBA[P(SiCl3)2] with sulfur-containing compounds under mild conditions. This method demonstrates the advantages of low energy consumption, mild reaction conditions and environmental friendliness. Moreover, this protocol-as a green synthesis method to replace the use of white phosphorus in the production of organophosphorus compounds (OPCs)-achieved the functional conversion of "inorganic phosphorus to organic phosphorus", in line with the national green development strategy.

Nickel-Catalyzed Three-Component Tandem Radical Cyclization 1,5-Difunctionalization of 1,3-Enynes and Alkyl Bromide.

A nickel-catalyzed three-component tandem radical cyclization reaction of aryl bromides with 1,3-enynes and aryl boric acids to construct γ-lactam-substituted allene derivatives has been described. This protocol provides lactam alkyl radicals through the free radical cyclization process, which can be effectively used to participate in the subsequent multicomponent coupling reaction so that 1,3-enynes could directly convert into corresponding poly-substituted allene compounds. In addition, this efficient method enjoys a broad substrate scope and provides a series of 1,5-difunctionalized allenes in a one-pot reaction.

Synthesis of C4-Aminated Carbazoles and Their Derivatives via Pd/NBE Chemistry.

Carbazole, as one of the most important organic frameworks, has been used in optoelectronic materials and biochemistry. However, the synthesis of C4-substituted carbazole has always been an unsolved problem. This report describes the one-step synthesis of C4-aminated carbazoles and their derivatives through the series reaction of C-H amination and arylation. The substrate scope is wide. C4-Amino carbazoles substituted by C2, C6, C7, and C8 methyl groups, especially carbazole derivatives of fused rings, pyridine, and dibenzofuran, can be synthesized.

Access to Polysubstituted Halophosphorylated Dihydrofurans via Halotrimethylsilane-Promoted Cascade Cyclization of γ-Hydroxyl Ynones with Diphenylphosphine Oxides.

A halotrimethylsilane (TMSX) accelerated cascade halophosphorylation and cycloisomerization of γ-hydroxyl ynones with diphenylphosphine oxides is presented. This methodology allows the one-step synthesis of practical polysubstituted halophosphorylated dihydrofuran derivatives. It is noteworthy that halotrimethylsilane functions as a halogenation reagent as well as a promoter to initiate this transformation. In addition, the reaction system can also be scaled up to gram quantities, and the produced halogenated compounds can undergo further derivatizations by Pd-catalyzed coupling reactions.

Photoinduced inverse vulcanization.

The inverse vulcanization (IV) of elemental sulfur to generate sulfur-rich functional polymers has attracted much recent attention. However, the harsh reaction conditions required, even with metal catalysts, constrains the range of feasible crosslinkers. We report here a photoinduced IV that enables reaction at ambient temperatures, greatly broadening the scope for both substrates and products. These conditions enable volatile and gaseous alkenes and alkynes to be used in IV, leading to sustainable alternatives for environmentally harmful plastics that were hitherto inaccessible. Density functional theory calculations reveal different energy barriers for thermal, catalytic and photoinduced IV processes. This protocol circumvents the long curing times that are common in IV, generates no H2S by-products, and produces high-molecular-weight polymers (up to 460,000 g mol-1) with almost 100% atom economy. This photoinduced IV strategy advances both the fundamental chemistry of IV and its potential industrial application to generate materials from waste feedstocks.