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The neurological complications following cardiovascular surgery can significantly affect the prognosis of patients. As a convenient and non⁃invasive intraoperative neurological monitoring method, transcranial Doppler ultrasonography (TCD) can provide real⁃time assessment of cerebral hemodynamics and microemboli signals, guide the development of neuroprotective strategies, and reduce the brain injury events. This review systematically summarizes the basic methods and technical performance of TCD monitoring, its clinical application in cardiovascular surgery, as well as the main limitations and future trends of this technology, in order to improve perioperative safety.

Catalytic enantioselection usually depends on differences in steric interactions between prochiral substrates and a chiral catalyst. We have discovered a carbene Si-H insertion in which the enantioselectivity depends primarily on the electronic characteristics of the carbene substrate, and the log(er) values are linearly related to Hammett parameters. A new class of chiral tetraphosphate dirhodium catalysts was developed; it shows excellent activity and enantioselectivity for the insertion of diarylcarbenes into the Si-H bond of silanes. Computational and mechanistic studies show how the electronic differences between the two aryls of the carbene lead to differences in energies of the diastereomeric transition states. This study provides a new strategy for asymmetric catalysis exploiting the electronic properties of the substrates.

An efficient catalytic asymmetric dearomatizing amination of 2-naphthols and phenols catalyzed by N,N′-dioxide-copper(I) complex as a chiral catalyst was presented. A variety of optically active β-naphthalenone compounds with a nitrogen-containing quaternary carbon stereocenter were obtained with high yield and enantioselectivity under mild reaction conditions. Mechanistic studies indicated that this Csp2–N dearomatizing coupling proceeds via 1,3-reductive elimination of phenolate-CuIII-amino intermediate in five-membered ring transition states. The origin of enantioselectivity has also been elucidated based on density functional theory calculations. [ABSTRACT FROM AUTHOR]

This article discusses the development of a nickel-catalyzed hydroalkynylation reaction of 1,3-dienes with simple alkynes. The researchers used a Xantphos ligand to achieve regioselective hydroalkynylation, producing a variety of allylic alkyne products. They optimized the reaction conditions by adding water, which increased the yield of the desired product. The method demonstrated excellent functional-group tolerance and a wide substrate scope for alkynes. The researchers also proposed a mechanism for the reaction based on previous studies. Further research will focus on asymmetric variants, expanding the reaction scope, and exploring synthetic applications. [Extracted from the article]

Arguably, water is an ideal hydrogen source for reduction reactions, however with significant difficulties in practice. In this work, water was utilized as a hydrogen source for the electrochemical reduction of benzoic acid esters in an undivided cell by electrolysis with either direct current or rapid alternating polarity current, depending on the electronic properties of the ester. Notably, reactions using D2O afforded valuable d2-benzyl alcohols, with D incorporation rates as high as 97%. Mechanistic studies revealed that the reaction pathway depended on the substrate. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The alkenylzincation of internal alkynes is an effective method for the synthesis of multi‐substituted conjugated dienes; however, the current catalytic systems for this reaction are limited in terms of substrate scope and selectivity control, which restricts its practical applications. Herein, we report the first iron‐catalyzed alkenylzincation of internal alkynes, which features mild conditions, simple operation, broad substrate scope (including aryl/alkyl, diaryl, and dialkyl acetylenes), excellent functional group tolerance (tolerating highly active functional groups such as ester, methylthio, amide, sulfonyl, cyano, etc.), and high activity (with a turnover number of up to 11500, the highest record for carbometallation reactions). Notably, the catalytic system described in this article also realized the highly selective vinylzincation of unfunctionalized internal alkynes as well as the alkenylzincation of unsymmetrical diarylacetylenes and dialkyl acetylenes, which have not been achieved with other catalytic systems reported in the literatures. The current study provides a highly selective access to synthetically important multi‐substituted conjugated dienes. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The design and synthesis of spirochroman‐2‐on‐4,1'‐indan‐7'‐ol (SCIOL) and its application for synthesizing chiral monophosphinite ligands are reported. The synthesis features a tandem double Friedel‐Crafts reaction/lactonization to construct the spiro framework and the desired racemic SCIOL was obtained via 6 steps with a total yield of 44.5%. Using an inclusion resolution with N‐benzylcinchonidinium chloride, the optical SCIOL could be obtained in good yields on a gram scale. The preliminary studies indicated that the corresponding chiral spiro monophosphinite ligands exhibit high catalytic activity and enantioselectivity (up to 94% ee) in the rhodium‐catalyzed asymmetric hydrogenation of N‐acetyl dehydroamino esters. These outcomes highlight the significant potential of SCIOL as a useful framework for the development of chiral spiro ligands. [ABSTRACT FROM AUTHOR]

The enantioselective addition of potent nucleophiles to ketenes poses challenges due to competing background reactions and poor stereocontrol. Herein, we present a method for enantioselective phosphoric acid catalyzed amination of ketenes generated from α‐aryl‐α‐diazoketones. Upon exposure to visible light, the diazoketones undergo Wolff rearrangement to generate ketenes. The phosphoric acid not only accelerates ketene capture by amines to form a single configuration of aminoenol intermediates but also promotes an enantioselective proton‐transfer reaction of the intermediates to yield the products. Mechanistic studies elucidated the reaction pathway and explained how the catalyst expedited the transformation and controlled the enantioselectivity. [ABSTRACT FROM AUTHOR]

Chiral benzylic amines are privileged motifs in pharmacologically active molecules. Intramolecular enantioselective radical C(sp3)−H functionalization by hydrogen‐atom transfer has emerged as a straightforward, powerful tool for the synthesis of chiral amines, but methods for intermolecular enantioselective C(sp3)−H amination remain elusive. Herein, we report a cationic copper catalytic system for intermolecular enantioselective benzylic C(sp3)−H amination with peroxide as an oxidant. This mild, straightforward method can be used to transform an array of feedstock alkylarenes and amides into chiral amines with high enantioselectivities, and it has good functional group tolerance and broad substrate scope. More importantly, it can be used to synthesize bioactive molecules, including chiral drugs. Preliminary mechanistic studies indicate that the amination reaction involves benzylic radicals generated by hydrogen‐atom transfer. [ABSTRACT FROM AUTHOR]

Free carbene readily causes multiple side reactions due to its high energy, thus its asymmetric transformation is very difficult. We present here our findings of high‐pKa Brønsted acid catalysts that enable free carbene insertion into N−H bonds of amines to prepare chiral α‐amino acid derivatives with high enantioselectivity. Under irradiation with visible light, diazo compounds produce high‐energy free carbenes that are captured by amines to form free ylide intermediates, and then the newly designed high‐pKa Brønsted acids, chiral spiro phosphamides, promote the proton transfer of ylides to afford the products. Computational and kinetic studies uncover the principle for the rational design of proton‐transfer catalysts and explain how the catalysts accelerate this transformation and provide stereocontrol. [ABSTRACT FROM AUTHOR]

Background: Extensive knowledge of allergic multimorbidities is required to improve the management of allergic diseases with the industrialization of China. However, the demography and allergen distribution patterns of allergic multimorbidities in China remain unclear, despite the increasing prevalence of allergies. Methods: This was a real-world, cross-sectional study of 1273 outpatients diagnosed with one or more allergic diseases in Guangzhou, the most populated city of southern China, with leading industrial and commercial centers, between April 2021 and March 2022. Seven allergic diseases (allergic rhinitis (AR), asthma (AS)/cough variant asthma (CVA), atopic dermatitis (AD)/eczema, food allergy (FA), allergic conjunctivitis (AC), drug allergy (DA), and anaphylaxis) were assessed. Positive rates of sensitization to different allergens were measured using an allergen detection system of the UniCAP (Pharmacia Diagnostics, Sweden) instrument platform to compare the groups of allergic multimorbidities against a single entity. Results: There were 659 (51.8%) males and 614 (48.2%) females aged from 4 months to 74 years included in the analysis. The study participants who were diagnosed with allergic diseases had an average of 1.6 diagnoses. Overall, 46.5% (592 of 1273) of the patients had more than one allergic condition, and allergic rhinitis was the most common type of multimorbidity. Women were more likely to suffer from an allergic disease alone, whereas allergic multimorbidities were more likely to be diagnosed in men (p = 0.005). In addition, allergic multimorbidities were common in all age groups, with an incidence ranging from 37.1% to 57.4%, in which children and adolescents were more frequently diagnosed with allergic multimorbidities than adults (18–60 years old) (all p < 0.05). Allergic multimorbidity was observed throughout the year. A difference in the positive rate of allergens sensitization and total immunoglobulin E (tIgE) levels between different allergic multimorbidities was observed. Conclusions: Allergic multimorbidities were very commonly found in nearly half of all patients with allergies. The proportion of allergic multimorbidities varied with the type of disease, sex, age, and allergen distribution pattern. These findings may help clinicians to develop "One health" strategies for the clinical management of allergic diseases. [ABSTRACT FROM AUTHOR]

We have developed a method for constructing tricyclic [1,2‐a]indoles via nickel‐catalyzed intramolecular imine‐alkene coupling reactions. This method enables syntheses of 6‐5‐5 and 6‐5‐6 tricyclic [1,2‐a]indoles. The use of NIXantphos or DPPPent as a ligand and 4‐(trifluoromethyl)benzoic acid as a co‐catalyst is crucial for the reaction. The synthetic utility of the method was demonstrated by converting the product into useful indole amines. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Hydrofluoride is an industry‐preferred fluoride source, and finds extensively application to manufacture diverse fluoro chemicals. The Et3N‐3HF complex is a liquid HF with improve safety. In this work, we report electrochemical synthesis of a series of sulfonyl fluoride with Et3N‐3HF as fluoride source. The sulfinic salt is a smell‐less, non‐volatile, and air‐stable sulfur source in this reaction. With the combination of Et3N‐3HF and aryl/alkyl sulfinic salt, the sulfonyl fluorides are achieved without the use of external oxidant. In addition, we demonstrate further advantage in a tandem reaction involving Pd‐catalyzed C—S cross‐coupling and formation of S—F bond. A variety of functional groups including amino acids, heterocycles, halides are well tolerated. [ABSTRACT FROM AUTHOR]

We have developed a nickel‐catalyzed desymmetric reductive cyclization/coupling of 1,6‐dienes. The reaction provides an efficient method for constructing a chiral tertiary alcohol and a quaternary stereocenter by a single operation. The method has excellent diastereoselectivity and high enantioselectivity, a broad substrate scope, as well as good tolerance of functional groups. Preliminary mechanism studies show that alkyl nickel(I) species are involved in the reaction. [ABSTRACT FROM AUTHOR]

The hydrogenation of esters catalyzed by a manganese complex of phosphine‐aminopyridine ligand was developed. Using this protocol, a variety of (hetero)aromatic and aliphatic carboxylates including biomass‐derived esters and lactones were hydrogenated to primary alcohols with 63–98% yields. The manganese catalyst was found to be active for the hydrogenation of methyl benzoate, providing benzyl alcohol with turnover numbers (TON) as high as 45,000. Investigation of catalyst intermediates indicated that the amido manganese complex was the active catalyst species for the reaction. [ABSTRACT FROM AUTHOR]