Rapid and Controlled Assembly of Polysubstituted Furans and Their Oligoaryls from Alkynes and Aldehydes Facilitated by Sequential Deprotonation.

A new sequential deprotonation strategy of dimethyl sulfoxide (DMSO) and propargyl alcohol in the presence of a base was developed for the generation of the α-hydroxyl carbanion, which enables rapid and controllable access to a wide range of valuable highly functionalized furans in one pot from alkynes and aldehydes under transition-metal- and additive-free conditions. Preliminary mechanistic studies revealed the crucial role of the base and DMSO. More importantly, deuterium labeling experiments confirmed the formation of the α-hydroxyl carbanion.

A Poly(2,7-anthrylene) with peri-Fused Porphyrin Edges.

Anthracene has served as an important building block of conjugated polymers with the connecting positions playing a crucial role for the electronic structures. Herein, anthracene units have been coupled through their 2,7-carbons to develop an unprecedented, conjugated polymer, namely, poly(2,7-anthrylene) featuring additional peri-fused porphyrin edges. The synthesis starts from a 2,7-dibromo-9-nickel(II) porphyrinyl-anthracene as the pivotal precursor.

Reductive Amination of Aldehyde and Ketone with Ammonia and H by an -Generated Cobalt Catalyst under Mild Conditions.

Herein, we present the simplest approach for the synthesis of primary amines via reductive amination using H as a reductant and aqueous ammonia as a nitrogen source, catalyzed by amorphous Co particles. The highly active Co particles were prepared by simply mixing commercially available CoCl and NaBH/NaHBEt without any ligand or support. This reaction system features mild conditions (80 °C, 1-10 bar), high selectivity (99%), a wide substrate scope, simple operation, and easy separation of the catalyst.

Direct hydrogenation of natural oils to fatty alcohols enabled by an alcoholysis/hydrogenation relay strategy and two-phase solvent system.

Direct hydrogenation of natural oils to fatty alcohols was achieved a relay strategy involving alcoholysis of natural oils followed by hydrogenation of fatty acid esters. A two-phase system was used to avoid catalyst poisoning by glycerol. This protocol is suitable for plant oils, animal fats and waste cooking oil.

Recent Advances in Reversible Liquid Organic Hydrogen Carrier Systems: From Hydrogen Carriers to Catalysts.

Liquid organic hydrogen carriers (LOHCs) have gained significant attention for large-scale hydrogen storage due to their remarkable gravimetric hydrogen storage capacity (HSC) and compatibility with existing oil and gas transportation networks for long-distance transport. However, the practical application of reversible LOHC systems has been constrained by the intrinsic thermodynamic properties of hydrogen carriers and the performances of associated catalysts in the (de)hydrogenation cycles. To overcome these challenges, thermodynamically favored carriers, high-performance catalysts, and catalytic procedures need to be developed.

Highly Efficient Depolymerization of Waste Polyesters Enabled by Transesterification/Hydrogenation Relay Under Mild Conditions.

The efficient depolymerization of polyesters under mild conditions remains a significant challenge. Herein, we demonstrate a highly efficient strategy for the degradation of a diverse array of waste polyesters as low to 80 °C, 1 bar H . The key to the success of this transformation relied on the initial transesterification of macromolecular polyester into more degradable oligomeric fragments in the presence of CH OH and the subsequent hydrogenation by the use of the rationally designed quinaldine-based Ru complex.

Recyclable Silver-Catalyzed Selective Hydrogenation of Imides to Primary Amines via Dual C-N Bond Cleavage.

We report the first heterogeneous catalytic hydrogenation of N-substituted imides and polyimide to generate primary amines, diols, and lactones. Catalyzed by Ag/TiO, this reaction proceeded smoothly in high yields and selectivities for -alkyl and -aryl phthalimides and -aryl succinimides, which also had activity for the degradation of waste polyimide plastics. In contrast to the typical Gabriel process, this reaction does not need any toxic reagent, and the byproducts are also very useful.

Near-Ambient-Temperature Dehydrogenative Synthesis of the Amide Bond: Mechanistic Insight and Applications.

The current existing methods for the amide bond synthesis acceptorless dehydrogenative coupling of amines and alcohols all require high reaction temperatures for effective catalysis, typically involving reflux in toluene, limiting their potential practical applications. Herein, we report a system for this reaction that proceeds under mild conditions (reflux in diethyl ether, boiling point 34.6 °C) using ruthenium PNNH complexes.

Imminent rupture of abdominal aortic aneurysm complicated by arteriovenous fistulaization and hepatorenal failure: case report and literature review.

Arteriovenous fistula (AVF) is a rare complication of the abdominal aortic aneurysm (AAA) with complex clinical features. However, AVF and AAA usually cause no symptoms except when they rupture. This case study demonstrated that ultrasonography was a rapid and non-invasive method for the initial assessment of AAA and AVF.

[Design and application of a patient's clothing for critical ultrasound examination].

At present, most of the common medical clothes in clinic are uniform medical clothes, but there is no special clothes for patients in intensive care unit (ICU). In recent years, with the extensive application of critical ultrasound in the field of critical medicine, it is obviously difficult to meet the clinical needs on traditional patients' clothes. Guangdong Provincial People's Hospital designed a patient's clothing for critical ultrasound examination.

Ethylene Glycol as an Efficient and Reversible Liquid Organic Hydrogen Carrier.

Hydrogen has long been regarded as an ideal alternative clean energy vector to overcome the drawbacks of fossil technology. However, the direct utilization of hydrogen is challenging, due to low volumetric energy density of hydrogen gas and potential safety issues. Herein, we report an efficient and reversible liquid to liquid organic hydrogen carrier system based on inexpensive, readily available and renewable ethylene glycol.

A Reversible Liquid Organic Hydrogen Carrier System Based on Methanol-Ethylenediamine and Ethylene Urea.

A novel liquid organic hydrogen carrier (LOHC) system, with a high theoretical hydrogen capacity, based on the unpresented hydrogenation of ethylene urea to ethylenediamine and methanol, and its reverse dehydrogenative coupling, was established. For the dehydrogenation only a small amount of solvent is required. This system is rechargeable, as the H -rich compounds could be regenerated by hydrogenation of the resulting dehydrogenation mixture.

Palladium-Catalyzed Ring-Forming Aminoalkenylation of Alkenes with Aldehydes Initiated by Intramolecular Aminopalladation.

A palladium-catalyzed aminopalladation reaction followed by nucleophilic addition with aldehydes and dehydration is described. This direct and operationally simple procedure provides a rapid and reliable approach to a wide range of functionalized tetrahydroisoquinolines with high selectivity. Mechanistic studies disclosed that the nucleophilic addition, performed via a highly ordered transition-state, is the turnover-limiting step in which the inherent β-hydride elimination of the key Csp -Pd species was controlled by the confined conformation and the nucleophilicity of the Csp -Pd bond was enhanced by the strong electron-donating effect of the nitrogen atom.

Highly Efficient Process for Production of Biofuel from Ethanol Catalyzed by Ruthenium Pincer Complexes.

A highly efficient ruthenium pincer-catalyzed Guerbet-type process for the production of biofuel from ethanol has been developed. It produces the highest conversion of ethanol (73.4%, 0.

Enantioselective Aminomethylamination of Conjugated Dienes with Aminals Enabled by Chiral Palladium Complex-Catalyzed C-N Bond Activation.

A novel highly enantioselective aminomethylamination of conjugated dienes with aminals catalyzed by a chiral palladium complex ligated with BINOL-derived chiral diphosphinite has been successfully developed. This reaction proceeds via a Pd-catalyzed cascade C-N bond activation, aminomethylation, and asymmetric allylic amination reaction under mild reaction conditions, providing a unique and efficient strategy for the synthesis of enantiomerically pure allylic 1,3-diamines.

Copper-catalyzed decarboxylative cross-coupling of cinnamic acids and ACCN via single electron transfer.

A novel and convenient method for the synthesis of β,γ-unsaturated nitriles using ACCN (1,1'-azobis(cyclohexane-1-carbonitrile)) as a cyano source was described. This reaction was amenable to a broad range of substrates and provided the desired β,γ-unsaturated nitriles containing an all-carbon quaternary carbon center in moderate yields with high selectivity via single electron transfer and decarboxylation.

Decarboxylative Alkylcarboxylation of α,β-Unsaturated Acids Enabled by Copper-Catalyzed Oxidative Coupling.

A facile and general method for copper-catalyzed decarboxylative alkylcarboxylation of cinnamic acids with dimethyl 2,2'-azobis(2-methylpropionate) has been developed. The scope and versatility of the reaction was demonstrated, and a broad range of substrates bearing electron-donating and -withdrawing groups on the aromatic rings were all compatible with this reaction to provide desired β,γ-unsaturated esters in moderate to good yields. Moreover, α,β-unsaturated acids with a carbonyl group on the γ-position of acrylic acids also smoothly proceeded to furnish the desired products in good yields.

Metal Bridging for Directing and Accelerating Electron Transfer as Exemplified by Harnessing the Reactivity of AIBN.

A new strategy for tuning the electron transfer between radicals and enolates has been developed. This method elicits the innate reactivity of AIBN with a copper catalyst and enables a cascade reaction with cinnamic acids. Electron paramagnetic resonance studies and control experiments indicate that the redox-active copper species not only activates the radical by coordination, but also serves as a bridge to bring the radical and nucleophile within close proximity to facilitate electron transfer.

Diboron as a reductant for nickel-catalyzed reductive coupling: rational design and mechanistic studies.

Diboron (B2pin2) has been identified as an efficient and environmentally benign reducing reagent for reductive coupling reactions for the first time, which enables the nickel-catalyzed reductive tetramerization of alkynes to be performed with high efficiency. Mechanistic and kinetic studies indicate that the facile reductive elimination to form the B-B bond from the dinuclear Ni-Ni complexes is responsible for the high efficiency. The activation enthalpy (ΔH(‡) = 56.

Palladium-catalyzed insertion of an allene into an aminal: aminomethylamination of allenes by C-N bond activation.

A new and atom-economic palladium-catalyzed aminomethylamination of allenes with aminals by CN bond activation is described. This direct and operationally simple method provides a fundamentally novel approach for the synthesis of 1,3-diamines. Mechanistic studies suggest that a unique cationic π-allylpalladium complex containing an aminomethyl moiety is generated as a key intermediate through the carbopalladation of the allene with a cyclometalated palladium-alkyl species.

Palladium-catalyzed difunctionalization of enol ethers to amino acetals with aminals and alcohols.

A new strategy was developed for intercepting the palladium-alkyl species generated in Heck reaction via nucleophilic addition prior to the step of migratory insertion, which leads to a new palladium-catalyzed difunctionalization of enol ethers with aminals and alcohols to afford amino acetals. Mechanistic studies suggested that the cationic cyclometalated Pd(II) complex generated by the oxidative addition of aminal to a Pd(0) species was crucial for this unusual transformation.

An efficient Rh/O2 catalytic system for oxidative C-H activation/annulation: evidence for Rh(I) to Rh(III) oxidation by molecular oxygen.

A novel and efficient Rh/O2 catalytic system has been developed and shown to catalyze highly efficient oxidative C-H activation/annulation reactions, producing a broad range of isoquinolinium salts with high turnover numbers (up to 740). Mechanistic studies provided strong evidence of facile oxidation of Rh(I) to Rh(III) by molecular oxygen facilitated by acid.

Palladium-catalyzed vinylation of aminals with simple alkenes: a new strategy to construct allylamines.

A novel, highly selective palladium-catalyzed vinylation reaction for the direct synthesis of allylic amines from styrenes and aminals has been established. The utility of this method was also demonstrated by the rapid synthesis of cinnarizine from aldehydes, amines, and simple alkenes in one-pot manner. Mechanistic studies suggested that the reaction proceeds through a valuable cyclometalated Pd(II) complex generated by the oxidative addition of aminal to a Pd(0) species.

Palladium-catalyzed oxidative carbonylation of benzylic C-H bonds via nondirected C(sp3)-H activation.

A new strategy for generating benzylpalladium reactive species from toluenes via nondirected C(sp(3))-H activation has been developed. This led to construction of an efficient Pd-catalyzed reaction protocol for the oxidative carboxylation of benzylic C-H bonds to form substituted 2-phenylacetic acid esters and derivatives from inexpensive, commercially available starting materials.