Gold-Catalyzed Cross-Coupling Reactions of Organoiodides with Disulfides: Access to Aryl Sulfides and Vinyl Sulfide Derivatives.

Thioethers and their derivatives play important roles in synthetic chemistry, medicinal chemistry, and materials science. Herein, we report a hemilabile P,N-ligand-assisted gold-catalyzed C-S cross-coupling reaction of organoiodides with disulfides. In this reaction, alkyl or aryl disulfides react smoothly with aryl or vinyl iodides to afford a series of aryl sulfide and vinyl sulfide derivatives in good to excellent yields.

Gold-Catalyzed Difunctionalization of Activated Alkynes with Organohalides: Access to 3-Arylated and Alkenylated Coumarin Derivatives.

Coumarin skeletons are significant structural units frequently used in the fields of synthetic chemistry, medicinal chemistry, and materials science. Herein, we report a hemilabile P,N-ligand-assisted gold-catalyzed difunctionalization of activated alkynes with organohalides. The reaction occurs effectively under mild conditions without requiring an external oxidant, producing a variety of 3-arylated and alkenylated coumarin derivatives in high to excellent yields.

Solo water-gelatinized starch enhances the barrier properties of starch/PBAT.

Glycerol-plasticized thermoplastic starch blending with biodegradable materials reduces costs and enhances toughness at the expense of deteriorating barrier properties. Herein, solo water-gelatinized corn starch (GCS) was melt-blended with polybutylene adipate terephthalate (PBAT) at 130 °C, and subsequent dehydration converted GCS into retrograded corn starch (RCS), yielding RCS-filled PBAT composites. As a barrier filler, RCS dispersed in smaller particles, combined with an interfacial compatibilizer, pentaerythritol monolaurate (PM), dramatically enhances the barrier properties.

Gold(I/III)-Catalyzed Sulfonylation of Aryl/Vinyl Iodides To Synthesize Aryl Sulfones.

A gold-catalyzed sulfonylation of aryl/vinyl iodides to synthesize aryl sulfones facilitated by the ligand-enabled Au(I)/Au(III) redox catalysis was developed. In the reaction, aryl sodium sulfinates or sulphinic acids can react smoothly with aryl/vinyl iodides to directly construct various aryl sulfones. The strong synthetic capabilities of sulfone synthesis are demonstrated by its easily available and handled reagents, good functional group compatibility, and late-stage application of complicated biomolecules.

Antitumor Effect of Peptide-Camptothecin Conjugate Targeting CD133 Protein.

The peptide-drug conjugate (PDC) has emerged as one of the new approaches for cancer therapy, which has the advantages of improved drug target ability and reduced adverse effects compared with the traditional chemotherapy. CD133 is a surface antigen specific to cancer stem cells, which are thought to be responsible for the self-renewal, proliferation, metastasis, and chemoresistance of cancer cells. A PDC for CD133 was designed by us, and it consists of CD133 targeting peptide LS-7 (amino acid sequence LQNAPRS), a pH-sensitive linker (succinyl), and a cytotoxic payload, the cytotoxic molecule camptothecin (CPT) with potent toxicity in vivo and in vitro.

Photocatalytic Hantzsch Ester-Mediated Pinacol-Type Coupling of Aldehydes and Ketones.

We have developed a photocatalyst-free reaction system that uses Hantzsch esters as photoreducing agents to promote the coupling of carbonyl compounds to 1,2-diols. The system fully utilizes the single electron transfer and proton donor roles of Hantzsch esters. The system shows a wide range of substrate application.

Preferred Electric Field Mechanism for Frustrated Lewis Pair Reactivity.

This study employs computational methods to investigate the mechanism of H activation by frustrated Lewis pair (FLP) species, including both intermolecular and intramolecular nitrothane/borane FLP systems. Previous studies have proposed two qualitative reactivity mechanism models to explain the facile cleavage of H by FLPs. The findings of this study support the electric field mechanism as the favorable pathway for H cleavage.

B(CF)/Chiral Phosphoric Acid Promoted Asymmetric C-3 -Difluoroalkylation of Quinoxalin-2-ones with Difluoroenoxysilanes.

The asymmetric Mannich-type reaction of quinoxalin-2-ones with difluoroenoxysilanes has been developed for the synthesis of chiral -difluoroalkylated quinoxalin-2-ones. The reaction worked in the presence of chiral phosphoric acid and B(CF) in THF at room temperature. The reaction exhibited a good substrate scope furnishing the products in good yields (up to 97%) with up to 96% .

Metal-Free Enantioselective 1,4-Addition of Diarylphosphine Oxides to α,β-Unsaturated Carboxylic Esters.

The catalytic asymmetric conjugate addition of phosphorus nucleophiles to unsaturated compounds, catalyzed by metallic or nonmetallic catalysts, has been extensively developed. However, the enantioselective transformations involving α,β-unsaturated carboxylic esters for constructing chiral c-p bonds have been rarely reported, particularly in metal-free processes. In this study, we present a novel metal-free methodology for enantioselective 1,4-addition of diarylphosphine oxides to α,β-unsaturated carboxylic esters using classical chiral oxazaborolidine catalysts.

Asymmetric 1,4-Addition of Diarylphosphine Oxides to α, β-Unsaturated 2-Acyl Imidazoles.

Here we introduce a metal-free, catalytic and enantioselective strategy from α,β-unsaturated 2-acyl imidazoles to the chiral phosphorous 2-acyl imidazoles. Interestingly, this methodology was catalyzed by the classical and commercial oxazaborolidine under mild conditions. This strategy features a wide range of substrates scope with good yields and excellent enantioselectivities.

Protective and Flame-Retardant Bifunctional Epoxy-Based Nanocomposite Coating by Intercomponent Synergy between Modified CaAl-LDH and rGO.

Extensive utilization in various settings poses extra requirements of coatings beyond just anticorrosion properties. Herein, 8-hydroxyquinoline (8-HQ) intercalated CaAl-based layered double hydroxide (CaAl-8HQ-LDH) was loaded on reduced GO (rGO) through a one-pot hydrothermal reaction, which was employed as the nanofiller endowing the epoxy (EP/CaAl-8HQ LDH@rGO) with excellent flame-retardancy while ensuring efficient protection for mild steel. Results of electrochemical impedance spectroscopy (EIS) demonstrated the durability of the EP/CaAl-8HQ LDH@rGO-coated specimen, with the impedance at the lowest frequency (||) maintained as 1.

Ultralong Stability of TiCT-MXene Dispersion Through Synergistic Regulation of Storage Environment and Defect Capping with Tris-HCl Buffering.

Aqueous MXene dispersion suffers from a bottleneck issue of oxidation, leading to its gradual deterioration and ultimately compromised physicochemical characteristics. Herein, Tris-HCl buffer is employed to stabilize the diluted TiCT-MXene dispersion (0.05 mg mL) through the synergy of its potent pH-regulation capability and capping effect toward oxidation-susceptible defects/edges.

Enantioselective Synthesis of C2-Quaternary Indolin-3-ones by Pt-Catalyzed Alkynylation of 2-Aryl-3-indol-3-one with Alkynylsilanes.

An efficient method for the synthesis of five-membered chiral propargylic amines from 2-aryl-3-indol-3-one and alkynylsilanes has been developed. The reaction proceeded under the catalytic system of PtCl, oxazoline-based ligand , Zn(CFCOO), and AcOH in DCE at 95 °C via in situ desilylation of TMS-alkynes. This methodology also highlights a new protocol for the in situ desilylation of alkynylsilanes.

Pd-Catalyzed Asymmetric Allylation Reaction of 2-Aryl-3-indol-3-ones with Allyltrimethylsilane.

An efficient method for the first ene-reaction of 2-aryl-3-indol-3-ones with allyltrimethylsilane has been developed for the first time. The reaction proceeded under the catalysis of Pd(OAc) and chiral phosphoric ligand in the presence of Cu(CFCOO)·HO, PivOH, and 5 Å molecular sieves in DMSO at 60 °C. The present methodology can avoid the impact of amine products generated by the reaction on the catalyst, and at the same time, the high catalytic activity of classical palladium catalysts still has catalytic ability for low electrophilic keto-imines.

Hydrogenation of Alkynes and Olefins Catalyzed by Quaternary Ammonium Salts.

Catalytic hydrogenation of unsaturated hydrocarbons to alkenes and alkanes using molecular hydrogen is one of the most fundamental transformations in organic synthesis. While methodologies involving transition metals as catalysts in homogeneous and heterogeneous processes have been well developed, metal-free catalytic hydrogenation offers an ideal approach for future chemistry. Herein, the common and inexpensive quaternary ammonium salts are first introduced as catalysts in the catalytic hydrogenation system for the transformations from alkynes or olefins into the corresponding olefins or alkanes.

Application of Oxazaborolidine Catalysts (CBS) on Enantioselective 1,4-Addition of Diarylphosphine Oxides to α,β-Unsaturated Thioesters.

Here, we report the first catalytic enantioselective 1,4-addition of diarylphosphine oxides to α,β-unsaturated thioesters. Importantly, the most common and commercial oxazaborolidine (CBS) was employed as a catalyst for its new application without being activated by strong protonic acids or Lewis acids and led to the chiral thioesters in excellent yields and enantioselectivities. Furthermore, this method features mild reaction conditions (room temperature and air-insensitive), good substrate tolerance, and easy scalability.

Cantharidin analogue alleviates dextran sulfate sodium-induced colitis in mice by inhibiting the activation of NF-κB signaling.

Ulcerative colitis is a chronic inflammatory disease with a remitting-relapsing clinical course, it has evolved into a global burden given its high incidence worldwide. Cantharidin (CTD) derivatives are a class of compounds whose structures characterized with a 7-oxabicyclo [2.2.

Photocatalytic Alkynylation of Hydrosilanes via Hydrogen Atom Transfer.

Alkynylsilanes are significant structural units frequently used in synthetic chemistry, medicinal chemistry, functional materials, and life sciences. Herein, we report a method for using a hydrogen atom transfer (HAT) strategy in combination with visible-light-driven photocatalysis to achieve a direct coupling reaction between benzene sulfonyl acetylene and tertiary silanes, and a diverse alkynylation of hydrosilanes in the presence of reactive groups was achieved with this strategy. It is important to note that dihydroalkyl/aryl silanes are also suitable for the protocol of HAT photocatalytic of 4CzIPN and quinuclidine.

Photocatalytic synthesis of alkynylsulfones and alkenylsulfones using sulfonylhydrazides and alkynes.

An efficient and energy saving photocatalytic coupling reaction of benzenesulfonyl hydrazide with bromoacetylene has been reported. A series of alkynylsulfones were obtained in up to 98% yield. In addition, changing the base from KHCO to KOAc can give the alkenylsulfone product.

Effect of Sodium Dodecyl Sulfate on Stability of MXene Aqueous Dispersion.

MXenes suffer from severe oxidation and progressive degradation in aqueous media due to its poor chemical stability. Herein, sodium dodecyl sulfate (SDS) is employed as an efficient protectant for long-term storage of Ti C T -MXene aqueous dispersion. Experimental data support SDS's capability to protect oxidation-prone sites on Ti C T nanosheets, providing extended colloidal stability of up to 213 days.

Progression in the Oxidation Stability of MXenes.

MXenes are under the spotlight due to their versatile physicochemical characteristics. Since their discovery in 2011, significant advancements have been achieved in their synthesis and application sectors. However, the spontaneous oxidation of MXenes, which is critical to its processing and product lifespan, has gotten less attention due to its chemical complexity and poorly understood oxidation mechanism.

Divergent Radical Cyclization and Hydroaminoalkylation of -Arylacrylamides Using Photoredox Catalysis.

The ability to selectively synthesize multiple products from the same sets of substrates is a highly appealing and challenging concept in synthetic chemistry. In this manuscript, we describe the visible-light photoredox intermolecular catalysis of -arylacrylamides that are α-C-H functionalized with aryl tertiary amines. The photocatalyst acts as a chemical switch to trigger two different reaction pathways and to obtain two different products from the same starting material.

Enantioselective Transformations from Nitriles to NH -α-Tertiary Amines.

Organic molecules, containing one or more amine chiral centers, are very common to see in natural products and medicines. Although a large number of methods have been developed to afford enantiopure amines, most of the known approaches are limited with various reasons. For example, many methodologies start from nitrogen protected and activated substrates, which usually need multistep operations and seriously decrease the atom economy.

Photocatalyst-free visible light driven synthesis of -dihaloenones from alkynes, tetrahalomethanes and water.

Photocatalytic reactions, in particular, processes without photosensitisers, have attracted increased attention due to their green aspect and high economic value and are considered valuable tools in organic synthesis. A new practical photocatalytic system was investigated in this study, and it can efficiently produce -dihaloenones by combining terminal alkynes with tetrahalomethanes (BrCCl and CBr) and water without a photocatalyst, and the yield can reach up to 87%. The catalytic system is straightforward, the raw materials are inexpensive and easy to obtain, and the operation is simple.

encapsulation of abundant WP/NiP heterointerfaces in N,P co-doped two-dimensional carbon frameworks for boosting hydrogen evolution electrocatalysis.

Rational design of an efficient hydrogen evolution reaction (HER) electrocatalyst continues to be a significant challenge for large-scale application of renewable electrochemical energy devices. Herein, an interface engineering strategy is elaborately developed to construct an advanced multi-active component HER electrocatalyst, in which abundant tungsten phosphide (WP) and nickel phosphide (NiP) heterogeneous interfaces are synchronously encapsulated in nitrogen and phosphorus co-doped two-dimensional carbon frameworks (WP-NiP@NPC) convenient solid-phase reaction and subsequent high-temperature pyrolysis. In particular, the type of solid precursor has a critical impact on the formation of a flake-like nanoskeleton and abundant WP/NiP heterointerfaces.