Selective Hydrofunctionalization of Alkenyl Fluorides Enabled by Nickel-Catalyzed Hydrogen Atoms and Group Transfer: Reaction Development and Mechanistic Study.

Due to the unique effect of fluorine atoms, the efficient construction of high-value alkyl fluorides has attracted significant interest in modern drug development. However, enantioselective catalytic strategies for the efficient assembly of highly functionalized chiral C(sp3)-F scaffolds from simple starting materials have been underutilized. Herein, we demonstrate a nickel-catalyzed radical transfer strategy for the efficient, modular, asymmetric hydrogenation and hydroalkylation of alkenyl fluorides with primary, secondary, and tertiary alkyl halides under mild conditions. The transformation provides facile access to various structurally complex secondary and tertiary α-fluoro amide products from readily available starting materials with excellent substrate compatibility and distinct selectivity. Furthermore, the utility of this method is demonstrated by late-stage modifications and product derivatizations. Detailed mechanistic studies and DFT calculations have been conducted, showing that the rate-determining step for asymmetric hydrogenation reaction is NiH-HAT toward alkenyl fluorides and the stereo-determining step is alcohol coordination to Ni-enolates followed by a barrierless protonation. The mechanism for the asymmetric hydroalkylation reaction is also delivered in this investigation.

Defluorinative Alkylboration of Alkenes Enabled by Dual Photoredox and Copper Catalysis.

A regioselectivity reversed three-component defluorinative alkylboration of alkenes with trifluoromethyls and bis(pinacolato)diboron via dual photoredox/copper catalysis is reported. The mild conditions are compatible with a wide array of nonactivated trifluoromethyl aromatics bearing electron-donating or electron-neutral substituents, trifluoroacetamides, and various nonactivated terminal and internal alkenes, enabling straightforward access to synthetically valuable γ-gem-difluoroalkyl boronates with high efficiency. Furthermore, this protocol is applicable to alkene-tethered trifluoromethyl aromatics to furnish gem-difluoromethylene-containing cyclic compounds. Synthetic applications and preliminary mechanistic studies are also presented.

Divergent 1,2-carboallylation of terminal alkynes enabled by metallaphotoredox catalysis with switchable triplet energy transfer.

We report a metallaphotoredox strategy for stereodivergent three-component carboallylation of terminal alkynes with allylic carbonates and alkyl trifluoroborates. This redox-neutral dual catalytic protocol utilizes commercially available organic photocatalyst 4CzIPN and nickel catalysts to trigger a radical addition/alkenyl-allyl coupling sequence, enabling straightforward access to functionalized 1,4-dienes in a highly chemo-, regio-selective, and stereodivergent fashion. This reaction features a broad substrate generality and a tunable triplet energy transfer control with pyrene as a simple triplet energy modulator, offering a facile synthesis of complex trans- and cis-selective skipped dienes with the same set of readily available substrates.

Management of a nursing unit in a COVID-19 shelter hospital in China: A case study.

OBJECTIVE: Fangcang shelter hospital is a form of large temporary hospital developed in China to tackle public health events. Through the case study and analysis of managing a nursing unit in a huge Fangcang shelter hospital transformed from the National Exhibition and Convention Center during the Omicron wave in Shanghai, China between April 9, 2022 and May 24, 2022, this paper aimed to highlight critical implications of public health nurses in health emergencies. DESIGN: A case study was conducted using data collected from a nursing unit with 570 beds. The five characteristics of management were organized as follows: human resource management, establishment and optimization of the core workflow, safety management of high-risk patients, the grid cooperation mechanism with patient volunteers, as well as humanistic nursing. RESULTS: Analysis of the data of the nursing unit indicated close team cooperation, efficient and orderly process scheduling, good outcomes of patients, and the indispensable role of volunteers. CONCLUSION: Practice indicated that nursing unit management in a large Fangcang shelter hospital is important to ensure medical order and efficiency. This practical experience can provide valuable reference and data to support for the nursing management of large-scale public health events, such as infectious disease epidemics.

[Chemical constituents of roots of Rodgersia aesculifolia].

The chemical compositions of Rodgersia aesculifolia were isolated and purified using a combination of silica gel, reverse phase silica gel, Sephadex LH-20 column chromatography, and semi-preparative HPLC. The structures were determined according to the physicochemical properties and spectroscopic data. The MTT method and the ABTS kit were used to measure the cytotoxicity and antioxidant capacity of all isolates, respectively. Thirty-four compounds were isolated from R. aesculifolia and elucidated as stigmastane-6ß-methoxy-3ß,5α-diol(1), stigmastane-3ß,5α,6ß triol(2), ß-sitosterol(3), ß-daucosterol(4), stigmast-4-en-3-one(5), bergenin(6), 11-ß-D-glucopyranosyl-bergenin(7), 11-O-galloybergenin(8), 1,4,6-tri-O-galloyl-ß-D-glucose(9), gallic acid(10), 3,4-dihydroxybenzoic acid methyl ester(11), ethyl gallate(12), ethyl 3,4-dihydroxybenzoate(13), caffeic acid ethyl ester(14), p-hydroxybenzeneacetic acid(15), 4-hydroxybenzoic acid(16), 2,3-dihydroxy-1-(4-hydroxy-3-methoxyphenyl)-propan-1-one(17), 3,7-dimethyl-2-octene-1,7-diol(18), crocusatin-B(19), neroplomacrol(20), geniposide(21), 3-hydroxyurs-12-en-27-oic acid(22), 3ß-trans-p-coumaroyloxy-olean-12-en-27-oic acid(23), aceriphyllic acid G(24), isolariciresinol(25), trans-rodgersinine B(26), cis-rodgersinine A(27), neo-olivil(28),(7S,8R)-dihydro-3'-hydroxy-8-hydroxy-methyl-7-(4-hydroxy-3-methoxy phenyl)-1'-benzofuranpropanol(29), 5,3',4'-trihydroxy-7-methoxyflavanone(30), quercetin 3-rutinoside(31), catechin-[8,7-e]-4ß-(3,4-dihydroxy-phenyl)-dihydro-2(3H)-pyranone(32), ethyl α-L-arabino-furanoside(33), and l-linoleoylglycerol(34). One new compound was discovered(compound 1), 25 compounds were first isolated from R. aesculifolia, and 22 compounds were first isolated from the Rodgersia plant. The results indicated that compounds 22-24 possessed cytotoxicity for HepG2, MCF-7, HCT-116, BGC-823, and RAFLS cell lines(IC_(50) ranged from 5.89 µmol·L~(-1) to 20.5 µmol·L~(-1)). Compounds 8-14 and 30-32 showed good antioxidant capacity, and compound 9 showed the strongest antioxidant activity with IC_(50) of(2.00±0.12) µmol·L~(-1).

Nickel-Catalyzed Markovnikov-Selective Hydrodifluoromethylation of Alkynes Using BrCF2 H.

A Markovnikov-selective hydrodifluoromethylation of alkynes with BrCF2 H via nickel catalysis is described. This protocol proceeds via a migratory insertion of nickel hydride to alkyne followed by a CF2 H-coupling, enabling straightforward access to diverse branched CF2 H-alkenes with high efficiency and exclusive regioselectivity. The mild condition applies to a wide array of aliphatic and aryl alkynes with good functional group compatibility. Mechanistic studies are presented to support the proposed pathway.

Site- and Stereoselective Synthesis of Alkenyl Chlorides by Dual Functionalization of Internal Alkynes via Photoredox/Nickel Catalysis.

Herein, we report a redox-neutral and atom-economical protocol to synthesize valuable alkenyl chlorides from unactivated internal alkynes and abundant organochlorides via photoredox and nickel catalysis. This protocol enables the site- and stereoselective addition of organochlorides to alkynes via chlorine photoelimination-initiated sequential hydrochlorination/remote C-H functionalization. The protocol is compatible with a wide range of medicinally relevant heteroaryl, aryl, acid, and alkyl chlorides for efficiently producing γ-functionalized alkenyl chlorides, exhibiting excellent regioselectivities and stereoselectivities. Late-stage modifications and synthetic manipulations of the products and preliminary mechanistic studies are also presented.

Specular Reflections Detection and Removal for Endoscopic Images Based on Brightness Classification.

Specular Reflections often exist in the endoscopic image, which not only hurts many computer vision algorithms but also seriously interferes with the observation and judgment of the surgeon. The information behind the recovery specular reflection areas is a necessary pre-processing step in medical image analysis and application. The existing highlight detection method is usually only suitable for medium-brightness images. The existing highlight removal method is only applicable to images without large specular regions, when dealing with high-resolution medical images with complex texture information, not only does it have a poor recovery effect, but the algorithm operation efficiency is also low. To overcome these limitations, this paper proposes a specular reflection detection and removal method for endoscopic images based on brightness classification. It can effectively detect the specular regions in endoscopic images of different brightness and can improve the operating efficiency of the algorithm while restoring the texture structure information of the high-resolution image. In addition to achieving image brightness classification and enhancing the brightness component of low-brightness images, this method also includes two new steps: In the highlight detection phase, the adaptive threshold function that changes with the brightness of the image is used to detect absolute highlights. During the highlight recovery phase, the priority function of the exemplar-based image inpainting algorithm was modified to ensure reasonable and correct repairs. At the same time, local priority computing and adaptive local search strategies were used to improve algorithm efficiency and reduce error matching. The experimental results show that compared with the other state-of-the-art, our method shows better performance in terms of qualitative and quantitative evaluations, and the algorithm efficiency is greatly improved when processing high-resolution endoscopy images.

Ligand-controlled stereodivergent alkenylation of alkynes to access functionalized trans- and cis-1,3-dienes.

Precise stereocontrol of functionalized alkenes represents a long-standing research topic in organic synthesis. Nevertheless, the development of a catalytic, easily tunable synthetic approach for the stereodivergent synthesis of both E-selective and even more challenging Z-selective highly substituted 1,3-dienes from common substrates remains underexploited. Here, we report a photoredox and nickel dual catalytic strategy for the stereodivergent sulfonylalkenylation of terminal alkynes with vinyl triflates and sodium sulfinates under mild conditions. With a judicious choice of simple nickel catalyst and ligand, this method enables efficient and divergent access to both Z- and E-sulfonyl-1,3-dienes from the same set of simple starting materials. This method features broad substrate scope, good functional compatibility, and excellent chemo-, regio-, and stereoselectivity. Experimental and DFT mechanistic studies offer insights into the observed divergent stereoselectivity controlled by ligands.

Visible-Light-Induced Nickel-Catalyzed Radical Cross-Couplings to Access α-Aryl-α-trifluoromethyl Alcohols.

A photochemically induced nickel-catalyzed radical cross-coupling of phthalimido trifluoroethanol with aryl bromides to furnish α-aryl-α-trifluoromethyl alcohols is reported. This reaction proceeds via a photoinduced charge transfer of an electron donor-acceptor complex between Hantzsch ester and phthalimido trifluoroethanol, followed by 1,2-hydrogen atom transfer, to generate the α-hydroxytrifluoroethyl radical for the cross-coupling of aryl bromides. No exogenous photocatalysts or stoichiometric metal reductants are required in this mild and operationally simple protocol. Broad substrate compatibility and excellent functional group tolerance are observed.

Psychological experience of Juvenile patients' parents in Fangcang shelter hospital during the Omicron wave of COVID-19 pandemic in Shanghai, China: a qualitative study.

OBJECTIVE: To explore the psychological experience of Juvenile patient's parents in Fangcang shelter hospital during the Omicron wave of COVID-19 pandemic. METHODS: A qualitative study was conducted by using a phenomenological research method. Sixteen parents of juvenile patients with COVID-19 were recruited from National Exhibition and Convention Center (Shanghai, China) Fangcang shelter hospital (FSH) using purposive sampling. Data were collected by face-to-face in-depth interviews over 27 days, from April 9 to May 6, 2022. The interview data were analyzed using Colaizzi seven-step analysis method. RESULTS: The psychological experiences of the parents of juvenile patients in the Fangcang shelter hospital were summarized into three themes: "perception regarding the FSH", "worried about the unmet needs of juvenile patients ", and "the psychological burden after discharge". These themes were classified into 9 sub-themes, including the acceptance of FSH, adaptability to FSH, concerns about cross-infection in the FSH, special needs of infants and young children, psychological needs of preschool children, the learning demands of school-age children, concern about re-positive, fear of sequelae, worry about social acceptance. CONCLUSION: Juvenile patients and their parents in the Fangcang shelter hospitals have both positive and negative experiences. It is suggested that facilities for minors should be planned in advance. Humanistic care for adolescent patients and health education for the public are also critical.

Light-Induced Divergent Cyanation of Alkynes Enabled by Phosphorus Radicals.

A photochemically induced selective and divergent cyanation reaction of alkynes, enabled by phosphorus radicals, is described. With the use of simple triarylphosphine as a co-catalyst, three cyanation reactions, including di-hydrocyanation, anti-Markovnikov hydrocyanation, and domino hydrocyanation/reduction, can be divergently achieved, furnishing a wide array of alkyl dinitriles, alkenyl nitriles, and alkyl nitriles under mild conditions. Terminal and internal alkynes are applicable with high efficiency and excellent selectivity. Synthetic applications for biologically active agents and preliminary experimental and computational mechanistic studies are reported.

New Terpenoids from Potentilla freyniana Bornm. and Their Cytotoxic Activities.

Two new A-ring contracted triterpenoids, madengaisu A and madengaisu B, and one undescribed ent-kaurane diterpenoid, madengaisu C, along with 20 known compounds were isolated from the roots of Potentilla freyniana Bornm. The structures were elucidated using extensive spectroscopic techniques, including 1D and 2D-NMR, HR-ESI-MS, ECD spectra, IR, and UV analysis. Moreover, all isolated constituents were evaluated for their anti-proliferative activity against RA-FLS cells and cytotoxic activities against the human cancer cell lines Hep-G2, HCT-116, BGC-823, and MCF-7. Ursolic acid and pomolic acid displayed moderate inhibitory activity in RA-FLS cells with IC50 values of 24.63 ± 1.96 and 25.12 ± 1.97 µM, respectively. Hyptadienic acid and 2α,3ß-dihydroxyolean-12-en-28-oic acid 28-O-ß-d-glucopyranoside exhibited good cytotoxicity against Hep-G2 cells with IC50 values of 25.16 ± 2.55 and 17.66 ± 1.82 µM, respectively. In addition, 2α,3ß-dihydroxyolean-13(18)-en-28-oic acid and alphitolic acid were observed to inhibit HCT-116 cells (13.25 ± 1.65 and 21.62 ± 0.33 µM, respectively), while madengaisu B and 2α,3ß-dihydroxyolean-13(18)-en-28-oic acid showed cytotoxic activities against BGC-823 cells with IC50 values of 24.76 ± 0.94 and 26.83 ± 2.52 µM, respectively, which demonstrated that triterpenes from P. freyniana may serve as therapeutic agents for RA and cancer treatment.

Randomized Controlled Trial of Modified Nasobiliary Fixation and Drainage Technique.

Objectives: We investigated the clinical efficacy of a modified nasobiliary fixation and drainage technique which was designed in an attempt to reduce unplanned extubation and tube blockage and improve bile drainage and the comfort of catheterized patients. Methods: From January 2019 to December 2020, 230 patients receiving Endoscopic nasobiliary drainage (ENBD) during hospitalization were recruited to this study. Participants were randomly allocated to 2 groups by using the block randomization method: in the control group: the conventional method of nasobiliary fixation was adopted after surgery; in the test group: intraoperative annular cutting of nasobiliary tubes was performed and the exposed catheter length was standardized. The modified "tube-nose-ear" three-step technique was performed after surgery. The clinical efficacy of a modified nasobiliary fixation and drainage technique was evaluated and compared between the test group and the control group. Results: The rate of unplanned extubation and incidence of complications were significantly lower in the test group than the control group. In addition, the rate of bilirubin decrease after drainage was higher in the test group. Patient discomfort during catheterization was also significantly reduced using the modified technique (P < 0.05). Conclusions: The modified technique of nasobiliary fixation and drainage technique can significantly reduce unplanned extubation and nasobiliary tube blockage after ENBD, facilitate biliary drainage, and improve patient comfort. This technique warrants wider application in clinical practice.

[Research progress on chemical constituents and pharmacological activities of Potentilla].

There are 200-500 species of Potentilla(Rosaceae) worldwide, among which 90 species are widely distributed in China and have a long history of ethnic medicinal use. According to our statistics, a total of 367 compounds have been isolated and identified from plants of this genus, including terpenoids, flavonoids, phenolic acids, tannins, and phenylpropanoids. The medicinal materials made from these plants mainly have antioxidative, blood sugar-lowering, anti-inflammatory, anti-tumor, cardiovascular system-protecting, neuroprotective, and hepatoprotective activities. This study systematically reviews the research progress on chemical constituents and pharmacological activities of Potentilla plants to provide a basis for further research and clinical application.

Catalyst-Free Intermolecular Sulfonyl/Fluoromethyl Heteroarylation of Vinyl Ethers via Visible-Light-Induced Charge Transfer.

We report a visible-light-induced three-component sulfonyl-heteroarylation of vinyl ethers with sulfinates and five-membered heteroaryl chlorides. This protocol proceeds via electron-donor-acceptor (EDA) complexes between sulfinates and heteroaryl chlorides, giving ß-sulfonyl alkyl five-membered heteroarenes with high efficiency and excellent regioselectivity under mild and catalyst-free conditions. Utilization of CF3 SO2 Na or CF2 HSO2 Na as coupling partners further achieves three-component fluoromethyl-arylation of vinyl ethers, furnishing a series of valuable CF3 /CF2 H-incorporated alkyl heterocycles under mild conditions.

Selective Fluoromethyl Couplings of Alkynes via Nickel Catalysis.

We describe here a Ni-catalyzed intermolecular carbo-fluoromethylation of alkynes with aliphatic halides and fluoromethyl halides (BrCF2 H and ICH2 F) in the presence of zinc, enabling the facile and selective access to a diverse range of biologically valuable CF2 H/CH2 F-incorporated alkenes with excellent regio- and stereoselectivity. Notably, merging intramolecular radical cyclization with fluoromethyl coupling enables the expedient constructions of CF2 H/CH2 F-incorporated lactones and lactams with high efficiency and selectivity. Mechanistic studies disclose that this catalytic protocol proceeds via a radical addition to an alkyne followed by selective coupling with the fluoromethyl unit.

Catalytic three-component dicarbofunctionalization reactions involving radical capture by nickel.

The catalytic dicarbofunctionalization of unsaturated π bonds represents a powerful platform for the rapid construction of complex motifs. Despite remarkable progress, novel and efficient methods for achieving such transformations under milder conditions with chemo-, regio-, and stereoselectivity still remain a significant challenge; thus, their development is highly desirable. Recently, the merging of nickel catalysis with radical chemistry offers a new and benign platform for the catalytic dicarbofunctionalization of unsaturated π bonds with unprecedented reactivity and selectivity. In this review, we summarize the recent advances in this area by underpinning the catalytic domino transformations involving radical capture by nickel to provide a clear overview of reaction designs and mechanistic scenarios.

Divergent Aminocarbonylations of Alkynes Enabled by Photoredox/Nickel Dual Catalysis.

A metallaphotoredox-catalyzed strategy for the selective and divergent aminocarbonylation of alkynes with amines and 1 atm of CO is reported. This synergistic protocol not only enables the Markovnikov-selective hydroaminocarbonylation of alkynes to afford α,ß-unsaturated amides, but also facilitates a sequential four-component hydroaminocarbonylation/radical alkylation in the presence of tertiary and secondary alkyl boronate esters, which allows for straightforward conversion of alkynes into corresponding amides. Preliminary mechanistic studies disclose that a photoinduced oxidative insertion of aniline and CO into nickel followed by a migratory insertion of (carbamoyl)nickel species could be involved.

Reductive hydrobenzylation of terminal alkynes via photoredox and nickel dual catalysis.

A photoredox/nickel dual catalyzed reductive hydrobenzylation of alkynes and benzyl chlorides by employing alkyl amines as a stoichiometric reductant is described. This synergistic protocol proceeds via Markovnikov-selective migratory insertion of an alkyne into nickel hydride, followed by cross-coupling with benzyl chloride, providing facile access to important 1,1-disubstituted olefins. This reaction enables the generation of nickel hydride by utilizing readily available alkyl amines as the hydrogen source. The mild conditions are compatible with a wide range of aryl and alkyl alkynes as well as chlorides.