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The development of novel synthetic methodologies to incorporate fluorine/s or fluoroalkyl group/s into the frameworks of organic molecules has become a highly prioritized research area because such modifications can tune their physiochemical and biological properties. In recent years, nucleophilic phosphine catalysis has been extensively explored to achieve this goal, and significant progress has been made. This review summarizes the methodological advancements of cycloaddition, addition and coupling reactions employing fluorinated building blocks as electrophilic and/or nucleophilic reaction partners under phosphine catalysis to construct structurally and synthetically valuable organofluorine compounds, with special emphasis on the synthetic strategies, proposed reaction mechanisms and synthetic utilities. [ABSTRACT FROM AUTHOR]

Lewis base and Brønsted base controlled chemodivergent annulations of α‐methyl substituted allenyl imide and o‐aminotrifluoroacetophenones are realized to afford highly valuable furo[3,2‐b]indol‐2‐ones and dihydroquinolines bearing a CF3‐substituted quaternary stereogenic center. The possible reaction mechanisms are proposed through deuterium labelling experiments. This work demonstrates the unprecedented dual reactivities of α‐methyl substituted allenyl imide with electrophilic−nucleophilic compounds in annulation reactions, and features chemodivergence in transforming allenyl imide through β'‐C−H functionalization via phosphine catalysis and β/γ‐bisfunctionalization via Brønsted base catalysis. [ABSTRACT FROM AUTHOR]

To increase the service life of mechanical parts under severe wear environment, composite coatings with wear resistance are required. Fe‐based/B4C composite coating is fabricated on the surface of ASTM 1045 steel by vacuum cladding and the microstructure, hardness, and wear behavior of the coating are investigated. The results show that the coating is mainly composed of the coating matrix of α‐Fe, [Fe, Ni] solid solution, and the strengthening phases of eutectic borides M2B and carboborides M23(C, B)6 with irregular block distribution. The dispersion strengthening and solution strengthening of the coating microstructures improve the overall hardness distribution of the coating, the microhardness, and macrohardness of the coating are greatly improved, which are better than that of quenched and tempered ASTM 1045 steel (QT45 steel) and NM400 steel. The results of abrasive wear test under different loads (130 N/45 N) indicate that wear scar of the coating become shorter and shallower due to the antiabrasive grinding effect of strengthening phases, and wear resistance is significantly greater than that of QT45 steel and NM400 steel. The main wear mechanisms associate with QT45 steel and NM400 steel involve plastic deformation and microcutting, whereas the coating is mainly a mix mode of plastic cutting and fatigue spalling. [ABSTRACT FROM AUTHOR]

Background: Docetaxel (DTX) exhibits antitumor effects against breast cancer by stabilizing microtubules and increasing the accumulation of reactive oxygen species (ROS). DTX extravasation during infusion often causes skin injury. The present study aimed to investigate the effects and mechanisms of icaritin (ICT) on DTX‐induced skin injury. Methods: The effects of ICT on the viability and apoptosis of HaCaT cells were measured by SRB assay and flow cytometry, respectively. Endogenous LC3 puncta and microtubules were determined by immunofluorescence. The number of mitochondria was measured by MitoTracker orange staining. ROS were determined by dihydroethidium staining. The expression of markers of ROS and autophagy were measured by western blotting. Chloroquine, compound D, and tamoxifen were employed as the inhibitor for autophagy and AMPK, estrogen receptors (ERs) modulator, respectively. Results: DTX inhibited the viability and decreased apoptosis of HaCaT cells, which can be rescued by ICT. ICT decreased microtubule bundles, increased the number of mitochondria, and attenuated ROS of HaCaT cells induced by DTX. ICT blocks autophagy and the autophagic flux. Compound C or tamoxifen diminished the protection effects of ICT on DTX‐treated HaCaT cells. Conclusion: ICT alleviates DTX‐induced skin injury by suppressing ROS, reducing microtubule bundles, and blocking autophagy via ERs. Our study indicated that ICT may be a potential candidate for DTX‐induced skin injury. [ABSTRACT FROM AUTHOR]

With the widespread use of PD‐1/PD‐L1 monoclonal antibodies (mAbs) in the treatment of multiple malignant tumors, they were also gradually applied to advanced renal cell carcinoma (aRCC). Nowadays, multiple PD‐1/PD‐L1 mAbs, such as nivolumab, avelumab, and pembrolizumab, have achieved considerable efficacy in clinical trials. However, due to the primary, adaptive, and acquired resistance to these mAbs, the efficacy of this immunotherapy is not satisfactory. Theories also vary as to why the difference in efficacy occurs. The alterations of PD‐L1 expression and the interference of cellular immunity may affect the efficacy. These mechanisms demand to be revealed to achieve a sustained and complete objective response in patients with aRCC. Tyrosine kinase inhibitors have been proven to have synergistic mechanisms with PD‐1/PD‐L1 mAb in the treatment of aRCC, and CTLA‐4 mAb has been shown to have a non‐redundant effect with PD‐1/PD‐L1 mAb to enhance efficacy. Although combinations with targeted agents or other checkpoint mAbs have yielded enhanced clinical outcomes in multiple clinical trials nowadays, the potential of PD‐1/PD‐L1 mAbs still has a large development space. More potential mechanisms that affect the efficacy demand to be developed and transformed into the clinical treatment of aRCC to search for possible combination regimens. We elucidate these mechanisms in RCC and present existing combination therapies applied in clinical trials. This may help physicians' select treatment options for patients with refractory kidney cancer. [ABSTRACT FROM AUTHOR]

A dual‐band stub (DBS) in a hybrid lumped and distributed configuration is presented in this paper, which comprises one lumped kernel circuit unit cell (KCUC) centered between two uniform transmission lines. Image parameter theory is imposed to extract the DBS phase and impedance bandwidth properties. An odd‐even mode resonant frequency ratio is defined, capable of determining all the DBS element values as well as regulating the DBS size and its second working bandwidth. By converting the lumped KCUC into a quasi‐lumped microstrip topology, a purely planar DBS is automatically implemented by employing the aggressive space mapping (ASM). Through the customized ASM process, the finalized DBS dimensions can be generated within just a few full‐wave simulations. The relatively high accuracy and efficiency of the ASM are affirmed by comparing its performance to those of the traditional direct optimization algorithms. As an example, a DBS with WLAN dual frequencies and extended bandwidth is designed and fabricated. The measured results agree well with the simulated results, justifying the DBS properties and its ad hoc ASM optimization technique. [ABSTRACT FROM AUTHOR]

Unprecedented phosphine‐catalyzed [4+1] cycloadditions of allenyl imides have been discovered using various N‐based substrates including methyl ketimines, enamines, and a primary amine. These transformations provide a one‐pot access to cyclopentenoyl enamines and imines, or (chiral) γ‐lactams through two geminal C−C bond or two C−N bond formations, respectively. Several P‐based key intermediates including a 1,4‐(bis)electrophilic α,β‐unsaturated ketenyl phosphonium species have been detected by 31P NMR and HRMS analyses, which shed light on the postulated catalytic cycle. The synthetic utility of this new chemistry has been demonstrated through a gram‐scaling up of the catalytic reaction as well as regioselective hydrogenation and double condensation to form cyclopentanoyl enamines and fused pyrazole building blocks, respectively. [ABSTRACT FROM AUTHOR]

The BINOL‐derived chiral phosphoric acid (R)‐TRIP is utilized as an organocatalyst in the asymmetric isoprenylboration reaction of aldehydes, wherein hydrogen‐bond interactions play a key role in the control of enantioselectivity. A wide arrays of enantioenriched dienyl homoallyl alcohols, including two natural products (−)‐Ipsdienol and (−)‐Ipsenol, have been successfully constituted. The synthetic application to chiral isoprenylated isobenzofuranone, vinyloxirane and cyclohexene derivatives has also been disclosed. [ABSTRACT FROM AUTHOR]

The scalable reaction is successfully performed using aryl and alkyl amidines as well as foramidine. [ABSTRACT FROM AUTHOR]