Ru(II)-catalyzed enantioselective C–H functionalization involving an enantiodetermining C–H cleavage step remains undeveloped. Here we describe a Ru(II)-catalyzed enantioselective C–H ...activation/annulation of sulfoximines with α-carbonyl sulfoxonium ylides using a novel class of chiral binaphthyl monocarboxylic acids as chiral ligands, which can be easily and modularly prepared from 1,1′-binaphthyl-2,2′-dicarboxylic acid. A broad range of sulfur-stereogenic sulfoximines were prepared in high yields with excellent enantioselectivities (up to 99% yield and 99% ee) via desymmetrization, kinetic resolution, and parallel kinetic resolution. Furthermore, the resolution products can be easily transformed to chiral sulfoxides and key intermediates for kinase inhibitors.
Enormous research interest is devoted to fabricating three-dimensional graphene-based gels (3D GBGs) toward improved conversion of solar energy by virtue of the intrinsic properties of single ...graphene and 3D porous structure characteristics. Here, this concise minireview is primarily focused on the recent progress on applications of 3D GBGs, including aerogels and hydrogels, in photocatalytic degradation of pollutants from water and air, such as organic pollutants, heavy metal ions, bacteria and gaseous pollutants. In particular, the preponderances of 3D GBG photocatalysts for environmental pollutants degradation have been elaborated. Furthermore, in addition to discussing opportunities offered by 3D GBG composite photocatalysts, we also describe the existing problems and the future direction of 3D GBG materials in this burgeoning research area. It is hoped that this review could spur multidisciplinary research interest for advancing the rational utilization of 3D GBGs for practical applications in environmental remediation.
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•3D graphene-based gels (3D GBGs) possess more active sites.•Porous structure of 3D GBGs promotes the photogenerated electrons transfer.•3D framework provides an ideal support for the active components.•Applications of 3D GBGs in photocatalytic environmental remediation are overviewed.
Abstract
The performance of transition metal hydroxides, as cocatalysts for CO
2
photoreduction, is significantly limited by their inherent weaknesses of poor conductivity and stacked structure. ...Herein, we report the rational assembly of a series of transition metal hydroxides on graphene to act as a cocatalyst ensemble for efficient CO
2
photoreduction. In particular, with the Ru-dye as visible light photosensitizer, hierarchical Ni(OH)
2
nanosheet arrays-graphene (Ni(OH)
2
-GR) composites exhibit superior photoactivity and selectivity, which remarkably surpass other counterparts and most of analogous hybrid photocatalyst system. The origin of such superior performance of Ni(OH)
2
-GR is attributed to its appropriate synergy on the enhanced adsorption of CO
2
, increased active sites for CO
2
reduction and improved charge carriers separation/transfer. This work is anticipated to spur rationally designing efficient earth-abundant transition metal hydroxides-based cocatalysts on graphene and other two-dimension platforms for artificial reduction of CO
2
to solar chemicals and fuels.
The prognostic factors and optimal treatment for the elderly patient with glioblastoma (GBM) were poorly understood. This study extracted 4975 elderly patients (≥ 65 years old) with histologically ...confirmed GBM from Surveillance, Epidemiology and End Results (SEER) database. Firstly, Cumulative incidence function and cox proportional model were utilized to illustrate the interference of non-GBM related mortality in our cohort. Then, the Fine-Gray competing risk model was applied to determine the prognostic factors for GBM related mortality. Age ≥ 75 years old, white race, size > 5.4 cm, frontal lobe tumor, and overlapping lesion were independently associated with more GBM related death, while Gross total resection (GTR) (HR 0.87, 95%CI 0.80-0.94, P = 0.010), radiotherapy (HR 0.64, 95%CI 0.55-0.74, P < 0.001), chemotherapy (HR 0.72, 95%CI 0.59-0.90, P = 0.003), and chemoRT (HR 0.43, 95%CI 0.38-0.48, P < 0.001) were identified as independently protective factors of GBM related death. Based on this, a corresponding nomogram was conducted to predict 3-, 6- and 12-month GBM related mortality, the C-index of which were 0.763, 0.718, and 0.694 respectively. The calibration curve showed that there was a good consistency between the predicted and the actual mortality probability. Concerning treatment options, GTR followed by chemoRT is suggested as optimal treatment. Radiotherapy and chemotherapy alone also provide moderate clinical benefits.
Natural nanostructures in low refractive index Cicada wings demonstrate ≤1% reflectance over the visible spectrum. We provide design parameters for Cicada-wing-inspired nanotip arrays as efficient ...light harvesters over a 300–1000 nm spectrum and up to 60° angle of incidence in both low-index, such as silica and indium tin oxide, and high-index, such as silicon and germanium, photovoltaic materials. Biomimicry of the Cicada wing design, demonstrating gradient index, onto these material surfaces, either by real electron cyclotron resonance microwave plasma processing or by modeling, was carried out to achieve a target reflectance of ∼1%. Design parameters of spacing/wavelength and length/spacing fitted into a finite difference time domain model could simulate the experimental reflectance values observed in real silicon and germanium or in model silica and indium tin oxide nanotip arrays. A theoretical mapping of the length/spacing and spacing/wavelength space over varied refractive index materials predicts that lengths of ∼1.5 μm and spacings of ∼200 nm in high-index and lengths of ∼200–600 nm and spacings of ∼100–400 nm in low-index materials would exhibit ≤1% target reflectance and ∼99% optical absorption over the entire UV–vis region and angle of incidence up to 60°.
The combination of achiral Cp*Rh(III) with chiral carboxylic acids (CCAs) represents an efficient catalytic system in transition metal‐catalyzed enantioselective C−H activation. However, this hybrid ...catalysis is limited to redox‐neutral C−H activation reactions and the adopt to oxidative enantioselective C−H activation remains elusive and pose a significant challenge. Herein, we describe the development of an electrochemical Cp*Rh(III)‐catalyzed enantioselective C−H annulation of sulfoximines with alkynes enabled by chiral carboxylic acid (CCA) in an operationally friendly undivided cell at room temperature. A broad range of enantioenriched 1,2‐benzothiazines are obtained in high yields with excellent enantioselectivities (up to 99 % yield and 98 : 2 er). The practicality of this method is demonstrated by scale‐up reaction in a batch reactor with external circulation. A crucial chiral Cp*Rh(III) intermediate is isolated, characterized, and transformed, providing rational support for a Rh(III)/Rh(I) electrocatalytic cycle.
An electrooxidative rhodium(III)/chiral carboxylic acid‐catalyzed enantioselective C−H annulation of sulfoximines with alkynes, is described. A broad range of enantioenriched 1,2‐benzothiazines are obtained in high yields with excellent enantioselectivities. A crucial chiral Cp*Rh(III) intermediate is isolated, characterized, and transformed, providing rational support for a Rh(III)/Rh(I) electrocatalytic cycle.
The first enantioselective synthesis of pyrrolyl-substituted triarylmethanes has been accomplished using a novel imidodiphosphoric acid catalyst, which is derived from two (R)-BINOL frameworks with ...different 3,3'-substituents. This strategy was also expanded to the synthesis of bis(indolyl)-substituted triarylmethanes with high enantioselectivities, which could only be obtained with moderate ee values in previous reports. These two efficient Friedel-Crafts alkylation processes feature low catalyst loading, broad functional group compatibilities, and the potential to provide practical pathways for the synthesis of enantioenriched bioactive triarylmethanes.
Elevated plasma statured fatty acids (FFAs) cause TLR4/MD2 activation‐dependent inflammation and insulin tolerance, which account for the occurrence and development of obesity. It has been confirmed ...that statured palmitic acid (PA) (the most abundant FFA) could bind MD2 to cause cellular inflammation. The natural compound celastrol could improve obesity, which is suggested via inhibiting inflammation, yet the detailed mechanism for celastrol is still unclear. As celastrol is reported to directly target MD2, we thought disrupting the binding between FFAs and MD2 might be one of the ways for celastrol to inhibit FFAs‐caused inflammation and insulin resistance. In this study, we found evidence to support our hypothesis: celastrol could reverse PA‐caused TLR4/MD2 activation‐dependent insulin resistance, as determined by glucose‐lowering ability, cellular glucose uptake, insulin action‐related proteins and TLR4/MD2/NF‐κB activation. Bioinformatics and cellular experiments showed that both celastrol and PA could bind MD2, and that celastrol could expel PA from cells. Finally, celastrol could reverse high fat diet caused hyperglycemia and obesity, and liver NF‐kB activations. Taking together, we proved that celastrol could reverses PA‐caused TLR4‐MD2 activation‐dependent insulin resistance via disrupting PA binding to MD2.
PA might through binding MD2 to and initiate TLR4/NF‐kappaB activation. Such activation impaired cellular glucose‐lowering ability. Disrupting PA‐cell binding, an action displayed by celastrol, is a novel strategy for treating hyperglycemia in obesity or other FFA‐caused, insulin resistance‐related disorders.
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