Discovery of Enantiopure ()-Methoprene Derivatives as Potent Biochemical Pesticide Candidates.

()-Methoprene has been widely applied as a powerful biochemical pesticide to control disease vectors and other pestiferous arthropods of economic importance. As a juvenile hormone analogue, many products based on ()-methoprene are developed and commercialized in the USA, Europe, and elsewhere. However, the agricultural use of ()-methoprene and its analogues remains underexplored.

Recent advances in catalytic enantioselective construction of monofluoromethyl-substituted stereocenters.

Chiral organofluorine compounds featuring a monofluoromethyl (CHF)-substituted stereocenter are often encountered in a number of drugs and bioactive molecules. Consequently, the development of catalytic asymmetric methods for the enantioselective construction of CHF-substituted stereocenters has made great progress over the past two decades, and a variety of enantioselective transformations have been accordingly established. According to the types of fluorinated reagents or substrates employed, these protocols can be divided into the following major categories: (i) enantioselective ring opening of epoxides or azetidinium salts by fluoride anions; (ii) asymmetric monofluoromethylation with 1-fluorobis(phenylsulfonyl)methane; (iii) asymmetric fluorocyclization of functionalized alkenes with Selectfluor; and (iv) asymmetric transformations involving α-CHF ketones, α-CHF alkenes, or other CHF-containing substrates.

H-Bond Donor-Directed Switch of Diastereoselectivity in the Enantioselective Intramolecular Aza-Henry Reaction of Ketimines.

We report an H-bond donor controlled diastereoselective switchable intramolecular aza-Henry reaction of ketimines derived from α-ketoesters and 2-(2-nitroethyl)anilines, allowing facile access to chiral tetrahydroquinolines bearing an aza-quaternary carbon stereocenter, which are privileged scaffold for medicinal researches. While newly developed cinchona alkaloid derived phosphoramide-bearing quaternary ammonium salt C2 selectively give cis-adducts in up to 20 : 1 dr and 99 % ee, the corresponding urea-bearing analogue C8 preferentially give trans-adducts in up to 20 : 1 dr and 99 % ee.

Organocatalytic enantioselective construction of Si-stereocenters: recent advances and perspectives.

Silicon-stereogenic chiral organosilanes have found increasing applications in synthetic chemistry, medicinal chemistry, and materials science. In this context, various asymmetric catalytic methods have been established for the diverse synthesis of silicon-stereogenic silanes. In particular, asymmetric organocatalysis is emerging as an important and complementary synthetic tool for the enantioselective construction of silicon-stereocenters, along with the rapid development of chiral-metal catalyzed protocols.

Highly extensile approach for comminuted ulna coronoid process fractures with mini-plate fixation: a case series of 31 patients.

Background: For the treatment of coronoid process fractures, medial, lateral, anterior, anteromedial, and posterior approaches have been increasingly reported; however, there is no general consensus on the method of fixation of coronal fractures. Here, we present a highly-extensile minimally invasive approach to treat coronoid process fractures using a mini-plate that can achieve anatomic reduction, stable fixation, and anterior capsular repair. Further, the study aimed to determine the complication rate of the anterior minimally invasive approach and to evaluate functional and clinical patient-reported outcomes during follow-up.

[ADAMTS13-Mediated Proteolytic Cleavage of Unusually Large von Willebrand Factor Polymers on Endothelial Cells in the Absence of Fluid Shear Stress].

Objective: To investigate the molecular mechanism of proteolytic cleavage of unusually large von Willebrand Factor(ULVWF) on endothelial cells by ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 repeats-13) in the absence of fluid shear stress, so as to provide a theoretical basis for the pathogenesis of thrombotic thrombocytopenic purpura (TTP) and other thrombotic disorders.

Methods: The ADAMTS13-mediated proteolysis of ULVWF on the surface of endothelial cells in the absence of fluid shear stress was observed through immunofluorescence microscopy. The variation in VWF antigen levels in the conditioned media were determined by ELISA assay.

Nickel-catalysed asymmetric hydromonofluoromethylation of 1,3-enynes for enantioselective construction of monofluoromethyl-tethered chiral allenes.

An unprecedented nickel-catalysed enantioselective hydromonofluoromethylation of 1,3-enynes is developed, allowing the diverse access to monofluoromethyl-tethered axially chiral allenes, including the challenging deuterated monofluoromethyl (CDF)-tethered ones that are otherwise inaccessible. It represents the first asymmetric 1,4-hydrofunctionalization of 1,3-enynes using low-cost asymmetric nickel catalysis, thus opening a new avenue for the activation of 1,3-enynes in reaction development. The utility is further verified by its broad substrate scope, good functionality tolerance, mild conditions, and diversified product elaborations toward other valuable fluorinated structures.

Reference values of gait parameters in healthy Chinese university students: A cross-sectional observational study.

Background: Gait is influenced by race, age, and diseases type. Reference values for gait are closely related to numerous health outcomes. To gain a comprehensive understanding of gait patterns, particularly in relation to race-related pathologies and disorders, it is crucial to establish reference values for gait in daily life considering sex and age.

Primary Breast Natural Killer/T-cell lymphoma with Cutaneous Involvement: A Case Report.

Objective: Extranodal natural killer/T-cell lymphoma comprises less than 1% of all non-Hodgkin lymphomas. It is rare in Western countries but is common in East Asia and Central and South America. The pathological features are angiocentricity /angioinvasion and significant tissue necrosis.

Ability of lactulose breath test results to accurately identify colorectal polyps through the measurement of small intestine bacterial overgrowth.

Background: While colorectal polyps are not cancerous, some types of polyps, known as adenomas, can develop into colorectal cancer over time. Polyps can often be found and removed by colonoscopy; however, this is an invasive and expensive test. Thus, there is a need for new methods of screening patients at high risk of developing polyps.

Nickel-catalyzed regio- and enantio-selective Markovnikov hydromonofluoroalkylation of 1,3-dienes.

A highly enantio- and regio-selective Markovnikov hydromonofluoro(methyl)alkylation of 1,3-dienes was developed using redox-neutral nickel catalysis. It provided a facile strategy to construct diverse monofluoromethyl- or monofluoroalkyl-containing chiral allylic molecules. Notably, this represents the first catalytic asymmetric Markovnikov hydrofluoroalkylation of olefins.

Me(CHCl)SiCF Facilitated Tandem Synthesis of Oxasilacycles Featuring a Trifluoromethyl Group.

An unprecedented tandem trifluoromethylsilylation/intramolecular S2 substitution sequence was realized by using bifunctional reagent Me(CHCl)SiCF, allowing efficient construction of valuable trifluoromethylated oxasilacyclohexanes that are difficult to access by known methods. Initial attempts into developing asymmetric variant reveal that using cinchonine-derived dimeric PTC catalyst could afford chiral oxasilacyclohexanes in up to 92% enantiomeric excess.

The Bifunctional Silyl Reagent Me (CH Cl)SiCF Enables Highly Enantioselective Ketone Trifluoromethylation and Related Tandem Processes.

We report the development of bifunctional trifluoromethylsilyl reagents for selective trifluoromethylation. The newly developed reagent, Me (CH Cl)SiCF , allows highly enantioselective trifluoromethylations of ketones with broad scope. Notably, by taking advantage of the chloromethyl group, a tandem synthesis of chiral trifluoromethylated oxasilacyclopentanes is developed, paving way to α-CF tertiary alcohols with vicinal tertiary or quaternary stereocenters.

Me(CH[double bond, length as m-dash]CH)SiCN: a bifunctional ethylene equivalent for Diels-Alder reaction based controllable tandem synthesis.

A bifunctional silyl reagent Me(CH[double bond, length as m-dash]CH)SiCN has been developed as a novel ethylene equivalent for the Diels-Alder (DA) reaction. The use of this reagent enables the controllable synthesis of value-added cyclohexenyl ketones or 2-acyl cyclohexancarbonitrile derivatives through a five- or six-step tandem sequence based on a Wittig/cyanosilylation/DA reaction/-cyanosilylation/isomerization sequence that involves a temporary silicon-tethered intramolecular DA reaction.

Enantioselective Synthesis of C-Tetrasubstituted -Hydroxyl-α-amino Nitriles via Cyanation of Ketonitrones Using Me(CHCl)SiCN.

Here, we report an unprecedented catalytic enantioselective cyanation of ketonitrones enabled by the bifunctional cyanating reagent Me(CHCl)SiCN. This approach allows facile access to optically active -hydroxyl-α-amino nitriles that are of high synthetic value but difficult to acquire by other methods. The use of bifunctional cyanating reagent Me(CHCl)SiCN not only achieves an enantioselectivity higher than that with TMSCN but also enables various diversification reactions of the resulting silylated adducts.

Organocatalytic enantioselective reactions involving prochiral carbocationic intermediates.

Since the discovery of carbocations in 1901, the past 120 years have witnessed many marvelous advances in the chemistry of carbocations. The state-of-the-art research in this field is to overcome the intrinsic instability and high reactivity of the prochiral carbocationic intermediates to develop catalytic asymmetric reactions. Such transformations enable the facile synthesis of structurally diverse value-added products from readily available starting materials such as alkenes, alcohols, and carbonyl derivatives, and enjoy high and even perfect atom-economy in most cases.

Catalyst-Free and Solvent-Controlled Divergent Synthesis of Difluoromethylene-Containing -Heterocycles.

An unprecedented catalyst-free reaction of benzo[]thiophene-2,3-diones with difluoroenoxysilanes has been developed using either MeOH or HO as the solvent, which constitutes a facile and efficient protocol for the solvent-controlled divergent synthesis of five- and seven-membered -heterocycles featuring a -difluoromethylene group. A gram-scale synthesis and the diversification of the product transformations to other difluorinated -heterocycles further highlight its utility.