Genomic, transcriptomic, and metabolomic analyses provide insights into the evolution and development of a medicinal plant Saposhnikovia divaricata (Apiaceae).

Saposhnikovia divaricata, 2n = 2x = 16, as a perennial species, is widely distributed in China, Mongolia, Russia, etc. It is a traditional Chinese herb used to treat tetanus, rubella pruritus, rheumatic arthralgia, and other diseases. Here, we assembled a 2.07 Gb and N50 scaffold length of 227.67 Mb high-quality chromosome-level genome of S. divaricata based on the PacBio Sequel II sequencing platform. The total number of genes identified was 42 948, and 42 456 of them were functionally annotated. A total of 85.07% of the genome was composed of repeat sequences, comprised mainly of long terminal repeats (LTRs) which represented 73.7% of the genome sequence. The genome size may have been affected by a recent whole-genome duplication event. Transcriptional and metabolic analyses revealed bolting and non-bolting S. divaricata differed in flavonoids, plant hormones, and some pharmacologically active components. The analysis of its genome, transcriptome, and metabolome helped to provide insights into the evolution of bolting and non-bolting phenotypes in wild and cultivated S. divaricata and lays the basis for genetic improvement of the species.

Double tract reconstruction improves the quality of life and better maintain the BMI of patients with proximal gastric cancer.

PURPOSE: The aim of this study is to investigate the effect of double-tract reconstruction on short-term clinical outcome, quality of life and nutritional status of patients after proximal gastrectomy by comparing with esophagogastrostomy and total gastrectomy with Roux-en-Y reconstruction. METHODS: The clinical data of patients who underwent double tract reconstruction (DTR), esophagogastrostomy (EG), total gastrectomy with Roux-en-Y reconstruction (TG-RY) were retrospectively collected from May 2020 to May 2022. The clinical characteristics, short-term surgical outcomes, postoperative quality of life and nutritional status were compared among the three groups. RESULTS: Compared with the DTR group, the operation time in the TG group was significantly shorter (200(180,240) minutes vs. 230(210,255) minutes, p < 0.01), and more lymph nodes were removed (28(22, 25) vs. 22(19.31), p < 0.01), there were no significant differences in intraoperative blood loss, first flatus time, postoperative hospital stay and postoperative complication rate among the three groups. Postoperative digestive tract angiography was completed in 36 patients in the DTR group, of which 21 (58.3%) showed double-tract type of food passing. The incidence of postoperative reflux symptoms was 9.2% in the DTR group, 43.8% in the EG group and 23.2% in the TG group, repectively (P < 0.01). EORTCQLQ-STO22 questionnaire survey showed that compared with EG group, DTR group had fewer reflux symptoms (P < 0.05), fewer anxiety symptoms (P < 0.05) and more swallowing symptoms (P < 0.05). Compared with TG group, DTR group had fewer reflux symptoms (P < 0.05). There were no other significant differences between the two groups. Compared with TG group and EG group, DTR can better maintain postoperative BMI, and there is no statistical difference between the three groups in terms of hemoglobin and albumin. CONCLUSIONS: Although partial double-tract reconstruction approach does not always ensure food to enter the distal jejunum along the two pathways as expected, it still shows satisfactory anti-reflux effect. Moreover, it might improve patients' quality of life and maintain better nutritional status comparing with gastroesophageal anastomosis and total gastrectomy with Roux-en-Y reconstruction.

Regiodivergent Hydrosilylation of Polar Enynes to Synthesize Site-Specific Silyl-Substituted Dienes.

Herein, we present catalyst-regulated switchable site-selective hydrosilylation of enynes, which are suitable for a wide range of alkyl and aryl substituted polar enynes and exhibit excellent functional group compatibility. Under the optimized conditions, silyl groups can be precisely installed at various positions of 1,3-dienes. While α- and γ-silylation products were obtained under platinum-catalytic systems, ß-silylation products were delivered with [Cp*RuCl]4 as catalyst. This process lead to the formation of 1,3-dienoates with diverse substitutions, which would pose challenges with other methodologies.

Cu-Catalyzed Regioselective Silylation of Chloro-Substituted Allenyl-Bdan.

A copper-catalyzed efficient regioselective silylation reaction of chloro-substituted allenyl-Bdan was developed. Under mild reaction conditions, allenyl and propargyl silane compounds can be selectively obtained in moderate to high yields by adjusting the bases and solvents used in the reactions. This study offers direct and efficient methods for synthesizing multifunctionalized allenyl and propargyl silane compounds from the same initial material of chloro-substituted allenyl-Bdan.

Docosahexaenoic Acid Supplementation for Neonatal Hyperbilirubinemia: A Double-Blind, Randomized Clinical Trial.

Docosahexaenoic acid (DHA) is an essential component for brain development during fetal and early postnatal life. Hyperbilirubinemia is characterized by abnormally high levels of bilirubin in the bloodstream, frequently leading to jaundice in newborns. In severe instances, this condition can progress to neurological damage or kernicterus, a form of brain damage. Initial cell-based experiments conducted by our research team revealed that DHA significantly enhances the survival rate of nerve cells treated with bilirubin and diminishes the oxidative stress indicated by reduced peroxide activity caused by unconjugated bilirubin (UCB). Further investigations through animal studies demonstrated that DHA effectively mitigates bilirubin-induced brain injury in neonatal rats. However, the potential of DHA to decrease the incidence of bilirubin-induced brain damage in clinical settings has not been previously explored or reported. Infants with neonatal hyperbilirubinemia (n = 30 per group) participated in a double-blind, randomized, placebo-controlled parallel study. They received either 100 mg/d DHA or placebo syrup immediately when they were diagnosed. The study found that the bilirubin level at 48 hours of treatment, serum neuron-specific enolase (NSE) levels, mean phototherapy duration, and abnormal rate of cranial magnetic resonance imaging (MRI) were lower in the DHA group than those in the control group (P < .05). These results suggested that DHA is effective as an adjuvant treatment for hyperbilirubinemia in children. It can reduce the incidence of neonatal hyperbilirubinemia brain injury and plays a certain protective role. Clinical study on protective effect of DHA on neonatal bilirubin injury is registered at Chinese Clinical Trial Registry as ChiCTR2300070250.

Hidden hotspots of amphibian biodiversity in China.

Identifying and protecting hotspots of endemism and species richness is crucial for mitigating the global biodiversity crisis. However, our understanding of spatial diversity patterns is far from complete, which severely limits our ability to conserve biodiversity hotspots. Here, we report a comprehensive analysis of amphibian species diversity in China, one of the most species-rich countries on Earth. Our study combines 20 y of field surveys with new molecular analyses of 521 described species and also identifies 100 potential cryptic species. We identify 10 hotspots of amphibian diversity in China, each with exceptional species richness and endemism and with exceptional phylogenetic diversity and phylogenetic endemism (based on a new time-calibrated, species-level phylogeny for Chinese amphibians). These 10 hotspots encompass 59.6% of China's described amphibian species, 49.0% of cryptic species, and 55.6% of species endemic to China. Only four of these 10 hotspots correspond to previously recognized biodiversity hotspots. The six new hotspots include the Nanling Mountains and other mountain ranges in South China. Among the 186 species in the six new hotspots, only 9.7% are well covered by protected areas and most (88.2%) are exposed to high human impacts. Five of the six new hotspots are under very high human pressure and are in urgent need of protection. We also find that patterns of richness in cryptic species are significantly related to those in described species but are not identical.

Instant and short-term effects of acupuncture for depression and anxiety in unstable angina pectoris patients with percutaneous coronary interventions.

Aim: Patients with unstable angina pectoris (UAP) usually present anxiety or depression during percutaneous coronary intervention (PCI). This study sought to investigate the instant and short-term effects of acupuncture for anxiety and depression in UAP patients with PCI. Methods: A total of 210 UAP patients who underwent PCI were recruited and randomly assigned (1:1:1) to acupuncture, placebo, or control groups. Enzyme-linked immunosorbent assay was used to detect the levels of fasting glucose, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), interleukin-6 (IL-6), high-sensitivity C-reactive protein (Hs-CRP), advanced oxidation protein products (AoPPs), and oxidized low-density lipoprotein (OX-LDL). Serial questionnaires with the Hamilton Anxiety (HAMA) scale and the Pittsburgh Sleep Quality Index were evaluated, and heart rate variability indicators were obtained. Results: Primary end-point: low frequency/high frequency (HF) was lower in the electroacupuncture group (p = 0.014), while standard deviation of normal-to-normal intervals, average standard deviation of normal-to-normal intervals, percentage of successive intervals that differ more than 50 ms, and HF were increased with acupuncture (p = 0.018, p = 0.043, p = 0.016, and p = 0.002, respectively). Secondary end-point: significant improvements in anxiety levels (HAMA) were observed in the three groups (p < 0.001). The fasting insulin and HOMA-IR levels were similar between the control group and the acupuncture group (p = 0.285 and p = 0.165, respectively). The levels of IL-6 and AoPPs differed among the three groups (p = 0.021 and p < 0.001, respectively). However, no significant differences were found in fasting plasma glucose, fasting c-peptide, Hs-CRP, and OX-LDL levels among the three groups (p = 0.585, p = 0.611, p = 0.902, and p = 0.756, respectively). Conclusions: In this study, short-term acupuncture may potentially relieve clinical symptoms before PCI treatment. Clinical Trial Registration: ClinicalTrials.gov, identifier (NCT03789344).

Design, synthesis and biological evaluation of 1,2,3-triazole benzothiazole derivatives as tubulin polymerization inhibitors with potent anti-esophageal cancer activities.

In this work, we utilized the molecular hybridization strategy to design and synthesize novel 1,2,3-triazole benzothiazole derivatives K1-26. The antiproliferative activities against MGC-803, Kyse30 and HCT-116 cells were explored, and their structure-activity relationship were preliminarily conducted and summarized. Among them, compound K18, exhibited the strongest proliferation inhibitory activity, with esophageal cancer cells Kyse30 and EC-109 being the most sensitive to its effects (IC50 values were 0.042 and 0.038 µM, respectively). Compound K18 effectively inhibited tubulin polymerization (IC50 = 0.446 µM), thereby hindering tubulin polymerize into filamentous microtubules in Kyse30 and EC-109 cells. Additionally, compound K18 induced the degradation of oncogenic protein YAP via the UPS pathway. Based on these dual molecular-level effects, compound K18 could induce G2/M phase arrest and cell apoptosis in Kyse30 and EC-109 cells, as well as regulate the expression levels of cell cycle and apoptosis-related proteins. In summary, our findings highlight a novel 1,2,3-triazole benzothiazole derivative K18, which possesses significant potential for treating esophageal cancers.

Influence of landform, soil properties, soil Cd pollution and rainfall on the spatial variation of Cd in rice: Contribution and pathway models based on big data.

Landform, soil properties, soil cadmium (Cd) pollution and rainfall are the important factors affecting the spatial variation of rice Cd. In this study, we conducted big data mining and model analysis of 150,000 rice-soil sampling sites to examine the effects by the above four factors on the spatial variation of rice Cd in Hunan Province, China. Specifically, the variable coefficient of rice Cd in space was significantly correlated with the partition scale according to the logistic fitting. The improved random forest results suggested that elevation (DEM) and pH were the two most important factors affecting the spatial variation of rice Cd, followed by relief, soil Cd content and rainfall. Typically, variance partitioning analysis (VPA) revealed that both the soil property and the interactive effects between the soil property and Cd pollution were the principal contributors to the rice-Cd variation, with the respective contributing rates of 30.5 % and 29.0 %. Meanwhile, the partial least square-structural equation modelling (PLS-SEM) elucidated 4 main paths of specific indirect effects on rice-Cd variation. They were landform → physicochemical property → soil acidity → rice-Cd variation, landform → soil acidity → rice-Cd variation, physicochemical property → soil acidity → rice-Cd variation, and soil texture → soil acidity → rice-Cd variation. This work can provide a general guidance for scientific zoning, accurate prediction and prevention of Cd pollution in paddy fields.

LINC02561 promotes metastasis in HCC via HIF1-α/NDRG1/UPF1 axis.

In the entire world, hepatocellular carcinoma (HCC) is one of the most frequent cancers that lead to death. Experiments on the function of long non-coding RNAs in the emergence of malignancies, including HCC, are ongoing. As a crucial RNA monitoring mechanism in eucaryotic cells, nonsense-mediated mRNA decay (NMD) can recognize and destroy mRNAs, which has an premature termination codons (PTC) in the open reading frame to prevent harmful buildup of truncated protein products in the cells. Nonsense transcript regulator 1 (Up-frameshift suppressor 1, UPF1), as a highly conserved RNA helicase and ATPase, plays a key role in NMD. Our laboratory screened out the highly expressed lncRNA LINC02561 in HCC from the TCGA database. Further research found that LINC02561 enhanced the invasion and transition abilities of liver cancer cells by regulating the protein N-Myc downstream regulated 1 (NDRG1). Hypoxia inducible factor-1 (HIF-1α) can bonded to LINC02561 promoters under hypoxic conditions, thereby promoting the upregulation of LINC02561 expression in liver cancer cells. LINC02561 competes with NDRG1 mRNA to bind UPF1, thereby preventing the degradation of NDRG1 mRNA to facilitate NDRG1 protein level. Taken together, the HIF1α-LINC02561-UPF1-NDRG1 regulatory axis could be an entirely novel target of liver cancer-related treatment.

Fecal calprotectin: A novel predictor of ulcerated esophageal injury after atrial fibrillation catheter ablation.

BACKGROUND: Atrial esophageal fistula (AEF) is a lethal complication that can occur post atrial fibrillation (AF) ablation. Esophageal injury (EI) is likely to be the initial lesion leading to AEF. Endoscopic examination is the gold standard for a diagnosis of EI but extensive endoscopic screening is invasive and costly. This study was conducted to determine whether fecal calprotectin (Fcal), a marker of inflammation throughout the intestinal tract, may be associated with the existence of esophageal injury. METHODS: This diagnostic study was conducted in a cohort of 166 patients with symptomatic AF undergoing radiofrequency catheter ablation from May 2020 to June 2021. Fcal tests were performed 1-7 days after ablation. All patients underwent endoscopic ultrasonography 1 or 2 days after ablation. RESULTS: The levels of Fcal were significantly different between the EI and non-EI groups (404.9 µg/g (IQR 129.6-723.6) vs. 40.4 µg/g (IQR 15.0-246.2), p < .001). Analysis of ROC curves revealed that a Fcal level of 125 µg/g might be the optimal cut-off value for a diagnosis of EI, giving a 78.8% sensitivity and a 65.4% specificity. The negative predictive value of Fcal was 100% for ulcerated EI. CONCLUSIONS: The level of Fcal is associated with EI post AF catheter ablation. 125 µg/g might be the optimal cut-off value for a diagnosis of EI. Negative Fcal could predict the absence of ulcerated EI, which could be considered a precursor to AEF.

Modeling and forecasting CO2 emissions in China and its regions using a novel ARIMA-LSTM model.

Since China joined the WTO, its economy has experienced rapidly growth, resulting in significantly increase in fossil fuel consumption and corresponding rise in CO2 emissions. Currently, China is the world's largest emitter of CO2, the regional distribution is also extremely uneven. so, it is important to identify the factors influence CO2 emissions in the three regions and predict future trends based on these factors. This paper proposes 14 carbon emission factors and uses the random forest feature ranking algorithm to rank the importance of these factors in three regions. The main factors affecting CO2 emissions in each region are identified. Additionally, an ARIMA + LSTM carbon emission predict model based on the inverse error combination method is developed to address the linear and nonlinear relationships of carbon emission data. The findings suggest that the ARIMA + LSTM is more accurate in predicting the trend of CO2 emissions in China. Moreover, the ARIMA + LSTM is employed to forecast the future CO2 emission trends in China's east, central, and west regions, which can serve as a foundation for China's CO2 emission reduction initiatives.

Clinical factors associated with severe surgical complications in patients with hypopharyngeal cancer: a single-center case-cohort study.

BACKGROUND: Surgical complications are a major concern in the surgical treatment of hypopharyngeal cancer. OBJECTIVE: To identify clinical factors that predispose patients with hypopharyngeal cancer to severe surgical complications. MATERIALS AND METHODS: The data of 449 patients who were underwent surgery as a part of the initial treatment with curative intent or as salvage treatment were retrospectively reviewed. The Chi-square test and logistic regression were used to evaluate the association of different factors with severe surgical complications. RESULTS: The incidence of severe complications was 22% (99/449), and 10 patients (2.2%) experienced rupture of the carotid artery. Multivariate analysis identified T3/4 stage (p = .002, odds ratio (OR) = 1.58, 95% confidence interval (CI) 1.177-2.122), radiotherapy (RT) (p < .001, OR = 2.744, 95% CI 1.680-4.482), diabetes mellitus (DM) (p = .007, OR = 2.697, 95% CI 1.308-5.56), and nonprimary closure (p = .008, OR = 1.992, 95% CI 1.193-3.327) as significant risk factors for severe surgical complications. CONCLUSIONS AND SIGNIFICANCE: T3/4 stage, RT, nonprimary closure, and DM were independent predisposing factors for severe surgical complications in our study population of hypopharyngeal cancer patients. Taking measures to lower the tumor stage and simplify the surgical procedure may be crucial in reducing the incidence of severe surgical complications among these patients.

Design, synthesis and biological evaluation of novel 2,4-diaminopyrimidine cinnamyl derivatives as inhibitors of FAK with potent anti-gastric cancer activities.

In this study, twenty-one novel 2,4-diaminopyrimidine cinnamyl derivatives as inhibitors targeting FAK were designed and synthesized based on the structure of TAE-226, and the inhibitory effects of these compounds on both the FAK enzyme and three cancer cell lines (MGC-803, HCT-116, and KYSE30) were investigated. Among them, compound 12s displayed potent inhibitory potency on FAK (IC50 = 47 nM), and demonstrated more significant antiproliferative activities in MGC-803, HCT-116 and KYSE30 cells (IC50 values were 0.24, 0.45 and 0.44 µM, respectively) compared to TAE-226. Furthermore, compound 12s significantly inhibited FAK activation leading to the negative regulation of FAK-related signaling pathways such as AKT/mTOR and MAPK signaling pathways. Molecular docking study suggested that compound 12s could well occupy the ATP-binding pocket site of FAK similar to TAE-226. In addition, compound 12s also efficiently inhibited the proliferation, induced apoptosis and cellular senescence in MGC-803 cells. In conclusion, compound 12s emerges a potent FAK inhibitor that could exert potent inhibitory activity against gastric cancer cells.

[Effects of Equal Amounts Silicon Fertilizer Application on Soil Bioavailability of Cadmium and Cadmium Uptake by Rice].

Cadmium (Cd) contamination of paddy fields is a global concern, as it can cause the accumulation of Cd in food. To explore the effects of equal application of silicon fertilizers on the bioavailability of cadmium and soil Cd uptake at different growth stages of rice, a field experiment was conducted with five silicon fertilizers under the same silicon dose (225 kg·hm-2). The results revealed that the Cd contents in roots, stems, and leaves increased with the extension of the rice growth stage. The application of silicon fertilizers reduced the Cd contents in roots, stems, and leaves in brown rice by 14.9%, 28.2%, and 12.2%, respectively. Compared with that in the control, the Cd content of brown rice in the SiCaMgFe and SiW treatments was decreased by 21.1% (P<0.05) and 21.2% (P<0.05), respectively. Similarly, Cd content in iron plaque (DCB-Cd) increased with the extension of the rice growth period, which accounted for 15.8%-42.8% of the total Cd content in roots, and the DCB-Cd content was different in each stage of rice. The content of exchangeable Cd (Exc-Cd) in soil at the mature stage of rice decreased by 36.4%, and the other fractions increased by 12.5%-48.2%. The results showed significant negative correlations between the Cd contents and Si in roots, DCB-Cd and soil available Cd and available Si, Exc-Cd and Car-Cd, and soil available Cd and pH value. Cd content in roots was positively correlated with DCB-Cd. With the equal dose of silicon fertilizer, the treatments of SiCaMgFe and SiW could effectively reduce the Cd content in rice. The application of silicon fertilizer promoted the transfer of Exc-Cd to Carb-Cd by increasing the soil pH value and the soil available Si content, meanwhile reducing the soil available Cd, Exc-Cd contents, the adsorption of Cd by the iron film on the root surface, and the adsorption capacity of iron plaque and root, thereby reducing the absorption of Cd by rice.

Synthesis and Transformation of Bis(silyl)-Substituted Conjugated Vinylallene Compounds.

We develop a copper-catalyzed disilylation of polysubstituted pent-1-en-4-yn-3-yl acetate derivatives, which in one pot furnishes the bis(silyl)-substituted vinylallenes in moderate yields under mild reaction conditions. The reaction shows broad substrate scope and single stereoselectivity. Besides, we develop a method to decrease the electrocyclization temperature of vinylallenes for the synthesis of methylenecyclobutenes by installing bis(silyl) substituents. And the effect of a silyl substituent on electrocyclization of vinylallenes was studied via DFT computation. The synthetic method features broad substrate scope and excellent stereoselectivity.

[Near-infrared targeted probe designed for intraoperative imaging of prostatic neurovascular bundles].

OBJECTIVE: To investigate the imaging effect of a near-infrared fluorescent targeted probe ICG-NP41 on the neurovascular bundles (NVB) around the prostate in rats. METHODS: A near-infrared fluorescent targeted probe ICG-NP41 was synthesized. An animal model for NVB imaging was established using Sprague-Dawley rats (250-400 g). Experiments were conducted using a custom-built near-infrared windowⅡ(NIR-Ⅱ) small animal in vivo imaging system, and images collected were processed using ImageJ and Origin. The fluorescence signal data were statistically analyzed using GraphPad Prism. The signal-to-background ratio (SBR) for NVB was quantitatively calculated to explore the effective dosage and imaging time points. Finally, paraffin pathology sections and HE staining were performed on the imaging structures. RESULTS: Except for rats in the control group (n=2), right-sided NVB of the rats injected with ICG-NP41 (n=2 per group) were all observed in NIR-Ⅱ fluorescence mode 2 h and 4 h after administration. At 2 h and 4 h, average SBR of cavernous nerve in 2 mg/kg group in fluorescence mode was 1.651±0.142 and 1.619±0.110, respectively, both higher than that in white light mode (1.111±0.036), with no significant difference (P>0.05); average SBR of 4 mg/kg group in fluorescence mode were 1.168±0.066 and 1.219±0.118, respectively, both higher than that in white light mode (1.081±0.040), with no significant difference (P>0.05). At 2 h and 4 h, the average SBR of 2 mg/kg and 4 mg/kg groups in fluorescence mode were higher than that of the control group (SBR=1), the average SBR of the 2 mg/kg group was higher than that of the 4 mg/kg group, and all the above with no significant difference (P>0.05). The average diameter of the nerve measured by full width at half maxima method was about (178±15) µm. HE staining of paraffin sections showed the right major pelvic ganglion. CONCLUSION: The near-infrared fluorescent targeted probe ICG-NP41 can be used for real-time imaging of the NVB around the prostate in rats, providing a potential feasible solution for localizing NVB in real time during nerve-sparing radical prostatectomy.

Advances in Phytochemistry and Modern Pharmacology of Saposhnikovia Divaricata (Turcz.) Schischk.

Saposhnikovia divaricata (Turcz.) Schischk (S. divaricata, Fangfeng) is a herb in the Apiaceae family, and its root has been used since the Western Han Dynasty (202 B.C.). Chromones and coumarins are the pharmacologically active substances in S. divaricata. Modern phytochemical and pharmacological studies have demonstrated their antipyretic, analgesic, anti-inflammatory, antioxidant, anti-tumor, and anticoagulant activities. Technological and analytical strategy theory advancements have yielded novel results; however, most investigations have been limited to the main active substances-chromones and coumarins. Hence, we reviewed studies related to the chemical composition and pharmacological activity of S. divaricata, analyzed the developing trends and challenges, and proposed that research should focus on components' synergistic effects. We also suggested that, the structure-effect relationship should be prioritized in advanced research.

A review of anorexia induced by T-2 toxin.

The presence of anorexia in animals is the most well-known clinical symptom of T-2 toxin poisoning. T-2 toxin is the most characteristic type A toxin in the trichothecene mycotoxins. The consumption of T-2 toxin can cause anorexic response in mice, rats, rabbits, and other animals. In this review, the basic information of T-2 toxin, appetite regulation mechanism and the molecular mechanism of T-2 toxin-induced anorectic response in animals are presented and discussed. The objective of this overview is to describe the research progress of anorexia in animals produced by T-2 toxin. T-2 toxin mainly causes antifeedant reaction through four pathways: vagus nerve, gastrointestinal hormone, neurotransmitter and cytokine. This review aims to give an academic basis and useable reference for the prevention and treatment of clinical symptoms of anorexia in animals resulting from T-2 toxin.

Regio- and enantioselective CuH-catalyzed 1,2- and 1,4-hydrosilylation of 1,3-enynes.

We report a copper-catalyzed ligand-controlled selective 1,2- and 1,4-hydrosilylation of 1,3-enynes, which furnishes enantiomerically enriched propargyl- and 1,2-allenylsilane products in high yields with excellent enantioselectivities (up to 99% ee). This reaction proceeds under mild conditions, shows broad substrate scope for both 1,3-enynes and trihydrosilanes, and displays excellent regioselectivities. Mechanistic studies based on deuterium-labeling reactions and density functional theory (DFT) calculations suggest that allenylcopper is the dominant reactive intermediate under both 1,2- and 1,4-hydrosilylation conditions, and it undergoes metathesis with silanes via selective four-membered or six-membered transition state, depending on the nature of the ligand. The weak interactions between the ligands and the reacting partners are found to be the key controlling factor for the observed regioselectivity switch. The origin of high enantiocontrol in the 1,4-hydrosilylation is also revealed by high level DLPNO-CCSD(T) calculations.