A catalytic asymmetric addition of arylboronic acids to isatins has been achieved by using chiral cationic C(2)-symmetric N-heterocyclic carbene (NHC) Pd(2+) diaqua complexes as the catalysts. The reaction can be performed under convenient conditions give corresponding adducts in good high yields (79-94%) and moderate excellent enantioselectivities (up 94% ee) presence LiOAr promoter which was generated situ.

Chiral N-phosphonyl imines were found to be efficient electrophiles for reaction with diethylaluminium cyanide, a non-volatile and inexpensive cyanide source. The produced chiral Strecker adducts, α-aminonitriles, in excellent chemical yields (94–98%) diastereoselectivities (95 : 5 >99%). This synthesis was confirmed follow the GAP chemistry (group-assistant-purification chemistry) process, which can avoid traditional chromatography recrystallization purifications, i.e., pure α-aminonitriles...

Abstract Ceramic bearing balls, characterized by their brittleness and low crack propagation resistance, demand rigorous quality control during manufacturing to ensure reliability durability. To address the limitations of conventional image processing methods in detecting intricate variable surface defects, this study proposes an improved YOLO11-based defect detection method tailored for ceramic balls. Leveraging its advanced feature extraction capabilities innovative network architecture,...

A series of α-amino-1,3-dithianes have been synthesized via the asymmetric Umpolung reaction 2-lithio-1,3-dithianes with chiral N-phosphonyl imines in good chemical yields (up to 82%) and excellent diastereoselectivities (>99:1). The manner by which are slowly added into solution 2-lithio-1,3-dithiane was found be crucial for achieving diastereoselectivity. current synthesis proven follow GAP chemistry (group-assistant-purification chemistry) process, avoids traditional purification...

Cumulene+carbene=chirality! Asymmetric additions of boronic acids to cumulene derivatives, catalyzed by an N-heterocyclic carbene–palladium complex, provide the desired allenic products in good excellent yields and moderate enantioselectivities. These optically active adducts can be further transformed useful chiral with intact chirality (see scheme).

Two kinds of <italic>ortho</italic>- and <italic>meta</italic>-oxazoline substituted NHC–gold(<sc>i</sc>) complexes have been synthesized. These gold could react with Selectfluor to give ionic chelated NHC–oxazoline gold(<sc>i</sc>) which smoothly catalyze the cycloaddition/oxidation reaction enynones alkene.

Gold catalyzed tandem [3,3]-rearrangement and intramolecular hydroamination of propargylic esters has been disclosed in this communication, producing a series 4-acyloxy-1,2-dihydroquinolines good yields high enantioselectivities.

The first example of palladium-catalyzed enantioselective desymmetrization 2,3-bicyclic hydrazines with arylboronic acids through a ring-opening process is described by using chiral C2-symmetric N-heterocyclic carbene (NHC) palladium complex as the catalyst. reaction can be performed under convenient conditions to give trans-1,2-disubstituted 3-cyclopentenes 3 high regioselectivity in good excellent yields (up 95%) and moderate enantioselectivities 88% ee).

The first series of chiral phosphine-imidazole carbene ligands based on a 1,1′-binaphthyl framework were synthesized from (R)-2-amine-2′-(diphenylphosphino)-1,1′-binaphthyl (1) in four-step pathway. After deprotonation these phosphine-imidazolium salts with LiOtBu, and subsequent complexation [Ir(COD)Cl]2 anion exchange NaBArF, phosphine-carbene chelated iridium complexes (R)-6a (R)-6b obtained. Their structures have been characterized by NMR X-ray diffraction analysis. NHC-phosphine rhodium...

In order to gain an understanding of the nature interactions among thiophene (TS), sulfone (TSO2), dibenzothiophene (DBT), (DBTO2) and ionic liquid N-butylpyridinium hydrogen sulfate ([BPY][HSO4]), a systematic investigation has been carried out using ab initio methods. The most stable structures indicate that both [BPY](+) [HSO4](-) play crucial roles in between TS, TSO2, DBT, DBTO2 [BPY][HSO4]. Analyses optimized suggest occurrence steric effects, π-π stacking bonds, dihydrogen bonds....

A universal method by considering different types of culture media can enable convenient classification bacterial species. The study combined hyperspectral technology and versatile chemometric algorithms to achieve the rapid non-destructive three kinds colonies (Escherichia coli, Staphylococcus aureus Salmonella) cultured on agar (Luria–Bertani (LA), plate count (PA) tryptone soy (TSA)). Based extracted spectral data, partial least squares discriminant analysis (PLS-DA) support vector...

Abstract An Au I /Au III catalytic system was found to be effective for the cascade oxidative arylation and cyclization of allenoates with arylboronic acids give corresponding cyclic adducts in moderate yields. This reaction constitutes a new method synthesis β‐aryl‐γ‐butenolides under mild conditions. Based on previous mechanistic studies, proposed redox cycle has been outlined.

The use of the chiral 1,1'-binaphthyl scaffold to construct ligands can be traced back for a long time. However, development bidentate NHC based on same backbone has only appeared recently. In this account, we describe design and synthesis new family demonstrate applications these NHC-metal complexes in catalyzed oxidative kinetic resolution secondary alcohols, asymmetric carbon-carbon bond formations, hydrosilylations, cyclizations 1,6-enynes. containing synthesized good yields from...

In an effort to understand the nature of interactions between pyridinium-based ionic liquids and thiophenic compounds, electronic topological properties N-butylpyridinium tetrafluoroborate ([BPY]+[BF4]−) thiophene (TS), benzothiophene (BT), dibenzothiophene (DBT) have been investigated by density functional theory. The most stable structure [BPY]+[BF4]− ion-pair indicated that hydrogen bonding fluorine atoms on [BF4]− anions C2–H2 pyridinium ring play important role in formation ion-pair....

When compared with the traditional manual design method, convolutional neural network has advantages of strong expressive ability and it is insensitive to scale, light, deformation, so become mainstream method in object detection field. In order further improve accuracy existing methods based on networks, this paper draws characteristics attention mechanism model color priors. Firstly, proposes a cognitive-driven prior obtain features for known types target samples overall scene,...

Abstract This paper presents the development of a new high-level design language called Feature based Design Description Language — FDDL. The traditional and computer-aided manufacturing procedures were analyzed important gaps between CAD CAM have been identified. These include lack uniform representation parts products, effective links CAM. FDDL is proposed designed in association with feature scheme as means integrating tasks planning. Its syntax, semantics vocabulary defined taking into...

A series of novel N-heterocyclic carbene-oxazoline ligands were synthesized in six steps. Palladium complexes obtained by deprotonation the benzimidazole salts and subsequent ligation with Pd(OAc)₂ THF. Different types cyclic bis- tetrapalladium achieved modifying substituent oxazoline group. The structures these palladium characterized NMR X-ray diffraction analysis. Catalytic properties Pd-complexes tested Suzuki–Miyaura cross-coupling reaction.

A foldable AMOLED display having less thickness, good bending reliability and high deformation recovery ability was obtained. Back supporting film in the OLED modules acts as a function base, novel polymer higher elasticity modulus, lower creep rate, residual deformation, which outperform then those conventional PET films, can lead to better folding properties. By comparing 48 hours static test of single HTHH environment, optimized 44% angle unrecovered after24 placing without force loading,...

Existing image classification methods based on convolutional neural networks usually use a large number of samples to learn features hierarchically, causing the problems over-fitting and error propagation layer by layer. Thus, they are vulnerable adversarial generated adding imperceptible disturbances input samples. To address above issue, we propose cognitive-driven color prior model memorize attributes target inspired characteristics human memory. At inference stage, priors indexed from...

Abstract The tetrapalladium complex (I) is found to be the most efficient catalyst for process.