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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.

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]

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]