Ytterbium(II) Complex-Catalyzed Selective Single and Double Hydrophosphination of 1,3-Enynes.

1,3-Enynes with conjugated alkene and alkyne moieties are attractive building blocks in synthetic chemistry. However, neither 4,1-hydrophosphination nor dihydrophosphination of 1,3-enynes has been reported. In this paper, the divalent ytterbium and calcium amide complexes supported by silaimine-functionalized cyclopentadienyl ligands (C5Me4-Si(L)=NR) were developed, which successfully catalyzed the efficient single and double hydrophosphination of 1,3-enynes with diarylphosphines. The hydrophosphination reactions selectively produced homoallenyl phosphines and (E)-propenylene diphosphines, respectively. This work demonstrated the potential of hemilabile silaimine-Cp ligands in the supporting the efficient and selective rare- and alkaline-earth catalysts.

A Silylene-Stabilized Germanium Analogue of Alkynylaluminum.

In contrast to the well-developed metal acetylides, the heavier analogues of the type REEM (E=Si, Ge, Sn, Pb; M=metals) have not been reported to date. Herein, we describe the synthesis of a silylene-stabilized germanium analogue of alkynylaluminum (4) by the reaction of a silylene-stabilized digermavinylidene (3) with 0.25 equiv of (AlCp*)4 in THF at 80 °C. The structure of 4 has been unambiguously characterized by spectroscopic analysis, X-ray diffraction analyses and DFT calculations, and features a linear AlGeGe skeleton with a Ge=Ge double bond and a polarized Ge-Al bond. Complex 4 shows excellent reactivity towards small molecules such as H2 , CS2 and TolNCO, and this allows for the construction of the structurally intriguing germylenyl aluminum complex (5) and the germacycles (6, 7).

Synthesis and Reactivity of N-Heterocyclic Silylene Stabilized Disilicon(0) Complexes.

Synthesis and reactivity of disilicon(0) complexes are of fundamental and application importance. Herein, we report the development of an N-heterocyclic imino-substituted silylene (1), which has strong σ-donating ability and is significantly sterically hindered. The one-pot reaction of this silylene with [IPr→SiCl2 ] (IPr=1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene) and KC8 (2 equiv) in THF at -30 °C leads to a silylene-ligated disilicon(0) complex (2), isolated as red crystals in 60 % yield. Characterization data and DFT calculations show that the trans-bent Si4 skeleton in 2 features a Si0 =Si0 double bond with significant π-π bonding and one lone pair of electrons on each of these two Si0 atoms. Complex 2 reacts readily with phenylacetylene, producing a structurally intriguing silatricyclic complex 6,8-diaza-1,2,5-trisilatricyclo-[3.2.1.02,7 ]-oct-3-ene (3), and revealing new aspects of low-valent silicon chemistry.

Catalytic Selective Dihydrosilylation of Internal Alkynes Enabled by Rare-Earth Ate Complex.

Hydrosilylation of alkynes generally yield vinylsilanes, which are inert to the further hydrosilylation because of the steric effects. Reported here is the first successful dihydrosilylation of aryl- and silyl-substituted internal alkynes enabled by a rare-earth ate complex to yield geminal bis- and tris(silanes), respectively. The lanthanum bis(amido) ate complex supported by an ene-diamido ligand proved to be the ideal catalyst for this unprecedented transformation, while the same series of yttrium and samarium alkyl and samarium bis(amido) ate complexes exhibited poor activity and selectivity, indicating significant effects of the ionic size and ate structure of the rare-earth catalysts.

Isolation of R6Si6 Dianion: A Bridged Tricyclic Isomer of Dianionic Hexasilabenzene.

A new strategy for the highly selective synthesis of tricyclo[2,2,0,02,5]hexasilanes R6Si6X2 (R = 2,4,6-Me3C6H2; X = H, Cl) and a bridged tricyclic R6Si6 dianion starting from the tetrachlorotrisilane RCl2SiSi(H)RSiCl2R (1) was described. Reduction of 1 with lithium naphthalene afforded tricyclohexasilane R6Si6H2 (2), which was halogenated to give the dichloride R6Si6Cl2 (3). Reduction of 3 with four equivalents of potassium graphite in the presence of 18-crown-6 afforded the first R6Si6 dianion (5) paired with [K(18-crown-6)]+2 counterions. The dianion 5 could act as a two-electron reductant toward transition metal halides and a nucleophile toward chlorosilanes. These reactions allowed the efficient and selective access to three types of silicon cages. The structures of the representative cages were confirmed by X-ray diffraction studies. Density functional theory calculations on 5 indicate that the negative charges are localized mainly on the anionic silicon atoms.

Synthesis of gem-Difluorinated Spiro-γ-lactam Oxindoles by Visible-Light-Induced Consecutive Difluoromethylative Dearomatization, Hydroxylation, and Oxidation.

Described herein is a protocol for visible-light-induced consecutive synthesis of gem-difluorinated spiro-γ-lactam oxindoles under mild conditions by means of a process involving sequential radical difluoromethylative dearomatization, hydroxylation, and oxidation. The protocol features high chemo- and regioselectivity, good functional group tolerance, and easy scalability. Several of the functionalized spirooxindole products showed good fungicidal activity, suggesting that they have potential agrochemical applications.

Merging Photoredox with Brønsted Acid Catalysis: The Cross-Dehydrogenative C-O Coupling for sp3 C-H Bond Peroxidation.

A photoredox and Brønsted acid synergistically catalyzed cross-dehydrogenative C-O coupling reaction is developed in which isochroman peroxyacetals are formed through sp3 C-H bond peroxidation. The reported method is characterized by its extremely mild reaction conditions, excellent yields, and broad substrate scope. An oxocarbenium ion p-chlorobenzenesulfonate was speculated to be the reactive intermediate. The role of hemiacetals and oxygenated dimers on the effective stabilization of the oxocarbenium ion was investigated; the presence of acid appeared to establish equilibrium between hemiacetals and oxygenated dimers with the oxocarbenium ion pairs. The broad applicability of the method highlights the potential of the protocol for molecule synthesis.

Clinicopathological features of gastric adenocarcinoma patients with metachronous distant metastasis.

Metachronous distant metastasis influences the postoperative survival of gastric adenocarcinoma patients with radical gastrectomy. We retrospectively reviewed 108 gastric adenocarcinoma patients with metachronous distant metastasis admitted to our hospital between January 2006 and December 2011. First, these patients were divided into two groups according to the time of metastasis: the early metastasis group (EMG) and late metastasis group (LMG). Second, according to the survival time after metastasis, these patients were divided into the longer survival group (LSG) and shorter survival group (SSG). Chi-square and Fisher exact tests were used to analyze associations between categorical variables. Survival data were estimated using the Kaplan-Meier method. Multivariate analyses of the prognostic factors related to overall survival were conducted using the Cox stepwise proportional hazards test. Results shows that the EMG was significantly associated with depth of invasion (p = 0.005), Union for International Cancer Control (UICC) stage (p = 0.003), degree of differentiation (p = 0.002), and vascular invasion (p = 0.001). The SSG was significantly associated with depth of invasion (p = 0.026) and normal carcinoembryonic antigen (CEA) level of after metastasis (p = 0.003). Survival analysis showed that depth of invasion (p < 0.001), degree of differentiation (p = 0.001), and vascular invasion (p = 0.011) were independent prognostic factors for gastric adenocarcinoma patients with metachronous distant metastasis. Gastric adenocarcinoma patients with metachronous distant metastasis exhibit characteristics that can be used to effectively estimate the possibility of early distant metastasis and the prognosis of these patients.

Rhodium(III)-Catalyzed C-H Activation and Annulation with 1-Alkynylphosphine Sulfides: A Mild and Regioselective Access for the Synthesis of Bulky Phosphine Ligands.

We reported herein rhodium(III)-catalyzed C-H activation and annulation reactions for the synthesis of bulky phosphine ligands by using 1-alkynylphosphine sulfides as key starting materials. In the presence of [Cp*RhCl2]2 (5 mol %) and CsOAc (2.0 equiv), various N-(pivaloyloxy)benzamides (3.0 equiv) could react smoothly with 1-alkynylphosphine sulfides at 40 °C in MeOH/CF3CH2OH cosolvent without external oxidant. Using [Cp(Ph)RhCl2]2 as catalyst, the reaction can be performed under less loading of benzamides (2.0 equiv) and milder reaction conditions (25 °C) with higher regioselectivity. In a sequential cyclization/desulfidation process, this new method provides a variety of bulky heteroarylphosphines with an isoquinolin-1(2H)-one motif.

Rhodium(III)-catalyzed cascade oxidative annulation reactions of aryl imidazolium salts with alkynes involving multiple C-H bond activation.

The cascade oxidative annulation reactions of aryl imidazolium salts with alkynes proceed efficiently in the presence of [Cp*RhCl2]2 and Cu(OAc)2·H2O to give substituted imidazo[1,2-a]-quinolinium salts and benzo[ij]imidazo[2,1,5-de]quinolizinium salts. The reactions were through the normal and abnormal N-heterocyclic carbene (NHC)-directed cyclometalation, alkyne insertion into the Rh-C bond, and reductive elimination of alkenyl and NHC ligands. The reactions are highly regioselective with unsymmetrical alkynes and can be achieved stepwise by controlling the reaction conditions. This provides a new application of NHCs as directing groups and substrates in the synthesis of fused N-heterocyclic compounds. The N-substituting group of the benzo[ij]imidazo[2,1,5-de]quinolizinium salts could be removed successfully with pyridine to afford benzo[ij]imidazo[2,1,5-de]quinolizines in excellent yields. Moreover, some of the benzo[ij]imidazo[2,1,5-de]quinolizinium salts exhibit intense fluorescence which might be useful in organic electronic materials.

Rhodium(III)-catalyzed intermolecular amidation with azides via C(sp³)-H functionalization.

The amidation reactions of 8-methylquinolines with azides catalyzed by a cationic rhodium(III) complex proceed efficiently to give quinolin-8-ylmethanamine derivatives in good yields via C(sp(3))-H bond activation under external oxidant-free conditions. A catalytically competent five-membered rhodacycle has been isolated and characterized, revealing a key intermediate in the catalytic cycle.

Synthesis, insecticidal activities and SAR of novel phthalamides targeting calcium channel.

In order to find novel and environmental friendly insecticides targeting the ryanodine receptor, three series of novel phthalamides containing heptafluoroisopropyl group, low fluorine atoms group and non-fluorine group were designed and synthesized. 35 novel structures of three series were obtained. Insecticidal activities of title compounds against oriental armyworm (Mythimna separata) and diamondback moth (Plutella xylostella) indicated that most of title compounds showed moderate to high activities at the tested concentration. The structure-activity relationship (SAR) was discussed in detail. During synthesizing title compounds B8, C7, D1, D9 and D12, their corresponding positional isomers (B8', C7', D1', D9' and D12') were afforded, and their structures were confirmed by 2D NMR. The calcium-imaging technique was also applied to investigate the effects of compounds B2, B10, C4 and C5 on the intracellular calcium ion concentration ([Ca(2+)]i), which indicated that they released stored calcium ions from endoplasmic reticulum, which denoted that some compounds are potential modulators of the insect ryanodine receptor (RyR).

Design, synthesis, and biological evaluation of 2-benzylpyrroles and 2-benzoylpyrroles based on structures of insecticidal chlorfenapyr and natural pyrrolomycins.

Based on structures of insecticidal chlorfenapyr and antibiotic natural pyrrolomycins, a series of new 2-benzylpyrroles and 2-benzoylpyrroles (with or without ethoxymethyl group on the nitrogen of pyrrole) were designed and synthesized. These compounds or their parent compounds possess weak acidity and high lipophilicity, the two characteristic properties for uncouplers of oxidative phosphorylation; therefore, they are expected to have insecticidal and acaricidal activity. The bioassay result verified that both 2-benzylpyrroles 17 and 2-benzoylpyrroles 19 had varied degrees of insecticidal activity against oriental armyworm depending on the substituents on the benzene ring, but they did not give any acaricidal activity. Conversely, most N-alkylated compounds 18 and 20 exhibited both insecticidal activity and acaricidal activity, of which compound 18i [4-bromo-2-(2,4-dichlorobenzyl)-1-(ethoxymethyl) -5-(trifluoromethyl) -1H-pyrrole-3-carbonitrile] has IC50 as low as 10-20 mg L(-1) on both activities.

Rhodium(III)-catalyzed alkenylation reactions of 8-methylquinolines with alkynes by C(sp3)-H activation.

The alkenylation reactions of 8-methylquinolines with alkynes, catalyzed by [{Cp*RhCl2}2], proceeds efficiently to give 8-allylquinolines in good yields by C(sp(3))-H bond activation. These reactions are highly regio- and stereoselective. A catalytically competent five-membered rhodacycle has been structurally characterized, thus revealing a key intermediate in the catalytic cycle.

CD3+/CD4+ cells combined with myosteatosis predict the prognosis in patients who underwent gastric cancer surgery.

BACKGROUND: This study aimed to investigate the predictive capacity of lymphocyte subpopulations, sarcopenia and myosteatosis for clinical outcomes in patients who underwent gastric cancer surgery. Additionally, the prognostic significance of CD3+/CD4+ cells in conjunction with myosteatosis was explored. METHODS: A cohort of 190 patients with gastric cancer who underwent surgery and received computed tomography scans between July 2016 and December 2017 at our institution was examined. Complete clinical information and peripheral lymphocyte subpopulations were available for all patients. A comprehensive array of statistical methodologies was employed to scrutinize variances in both clinical and pathological characteristics among patients, with the aim of identifying autonomous prognostic determinants requisite for the development of a nomogram. Subsequent assessment of the predictive efficacy of the nomogram was conducted via calibration curve analysis. RESULTS: The study comprised a cohort of 190 participants, encompassing 126 males (66.32%) and 64 females (33.68%), with a mean age of 58.47 (±11.37) years. Patients were stratified into three groups based on CD3+/CD4+ cells and myosteatosis, with 24 in Group 1, 87 in Group 2 and 79 in Group 3. Notably, patients in the third group exhibited significantly shorter progression-free survival (PFS) (hazard ratio [HR] = 0.208, P < 0.001) and overall survival (OS) (HR = 0.193, P < 0.001). The subset of peripheral blood lymphocytes exhibited elevated levels of CD3+/CD4+ cells (HR = 2.485, P < 0.001) and heightened CD4+/CD8+ ratios (HR = 1.705, P = 0.038), whereas diminished CD19+ cell counts (HR = 0.210, P = 0.032) correlated with improved OS in patients. The individuals presenting with sarcopenia (HR = 4.089, P = 0.023) and myosteatosis (HR = 2.857, P < 0.001) displayed reduced OS. The multivariate Cox regression analysis showed that pathological tumour-node-metastasis stage, CD19+ cells, sarcopenia and CD3+/CD4+ cell-myosteatosis were identified as independent prognostic factors for PFS and OS in patients. The constructed nomograms for PFS and OS yielded C-index values of 0.839 (95% confidence interval [CI]: 0.798-0.880) and 0.836 (95% CI: 0.792-0.879), respectively. The calibration analysis demonstrated that the nomograms accurately predicted the 3- and 5-year survival rates of PFS and OS in patients. CONCLUSIONS: Lymphocyte subsets, including CD3+/CD4+ cells, CD4+/CD8+ ratio and CD19+ cells, are indicative of clinical prognosis in gastric cancer surgery patients. Body composition parameters, such as sarcopenia and myosteatosis, are also associated with the patient's prognosis. The combination of CD3+/CD4+ cells with myosteatosis demonstrates enhanced prognostic value, enabling the identification of patients at high risk of post-operative metastasis and recurrence.

Evaluating the influence of sarcopenia and myosteatosis on clinical outcomes in gastric cancer patients undergoing immune checkpoint inhibitor.

BACKGROUND: The development and progression of gastric cancer (GC) are closely linked to the nutritional status of patients. Although immunotherapy has been demonstrated to be clinically effective, the relationships of sarcopenia and myosteatosis with the use of immune checkpoint inhibitors (ICIs) in patients with gastric cancer remain to be characterized. AIM: To assess the effects of sarcopenia and myosteatosis on the clinical outcomes of patients with GC undergoing treatment with an ICI. METHODS: We performed a retrospective study of patients who were undergoing immunotherapy for GC. For the evaluation of sarcopenia, the optimal cut-off value for the skeletal muscle index was established using receiver operating characteristic analysis of data obtained from pre-treatment computed tomography images at the L3 vertebral level. Myosteatosis was defined using the mean skeletal muscle density (SMD), with a threshold value of < 41 Hounsfield units (HU) for patients with a body mass index (BMI) < 25 kg/m² and < 33 HU for those with a BMI ≥ 25 kg/m². The log-rank test was used to compare progression-free survival (PFS) and overall survival (OS), and a Cox proportional hazard model was used to identify prognostic factors. Nomograms were developed to predict the PFS and OS of patients on the basis of the results of multivariate analyses. RESULTS: We studied 115 patients who were undergoing ICI therapy for GC, of whom 27.4% had sarcopenia and 29.8% had myosteatosis. Patients with sarcopenia or myosteatosis had significantly shorter PFS and OS than those without these conditions. Furthermore, both sarcopenia and myosteatosis were found to be independent predictors of PFS and OS in patients with GC administering an ICI. The prediction models created for PFS and OS were associated with C-indexes of 0.758 and 0.781, respectively. CONCLUSION: The presence of sarcopenia or myosteatosis is a reliable predictor of the clinical outcomes of patients with GC who are undergoing treatment with an ICI.

Metabolomic machine learning predictor for diagnosis and prognosis of gastric cancer.

Gastric cancer (GC) represents a significant burden of cancer-related mortality worldwide, underscoring an urgent need for the development of early detection strategies and precise postoperative interventions. However, the identification of non-invasive biomarkers for early diagnosis and patient risk stratification remains underexplored. Here, we conduct a targeted metabolomics analysis of 702 plasma samples from multi-center participants to elucidate the GC metabolic reprogramming. Our machine learning analysis reveals a 10-metabolite GC diagnostic model, which is validated in an external test set with a sensitivity of 0.905, outperforming conventional methods leveraging cancer protein markers (sensitivity < 0.40). Additionally, our machine learning-derived prognostic model demonstrates superior performance to traditional models utilizing clinical parameters and effectively stratifies patients into different risk groups to guide precision interventions. Collectively, our findings reveal the metabolic landscape of GC and identify two distinct biomarker panels that enable early detection and prognosis prediction respectively, thus facilitating precision medicine in GC.

Regioselective C2 Oxidative Olefination of Indoles and Pyrroles through Cationic Rhodium(III)-Catalyzed C-H Bond Activation.

Be economic with your atoms! An efficient Rh-catalyzed oxidative olefination of indoles and pyrroles with broad substrate scope and tolerance is reported. The catalytic reaction proceeds with excellent regio- and stereoselectivity. The directing group N,N-dimethylcarbamoyl was crucial for the reaction and could be removed easily.

Investigation and comparison of the mechanistic steps in the [(Cp*MCl2)2] (Cp* = C5Me5; M = Rh, Ir)-catalyzed oxidative annulation of isoquinolones with alkynes.

The mechanism of the [(Cp*MCl(2))(2)] (M = Rh, Ir)-catalyzed oxidative annulation reaction of isoquinolones with alkynes was investigated in detail. In the first acetate-assisted C-H-activation process (cyclometalated step) and the subsequent mono-alkyne insertion into the M-C bonds of the cyclometalated compounds, both Rh and Ir complexes participated well. However, the desired final products, dibenzo[a,g]quinolizin-8-one derivatives, were only formed in high yield when the Rh species participated in the final oxidative coupling of the C-N bond. Moreover, a Rh(I) sandwich intermediate was isolated during this transformation. The iridium complexes were found to be inactive in the oxidative coupling processes. All of the relevant intermediates were fully characterized and determined by single-crystal X-ray diffraction analysis. Based on this mechanistic study, a Rh(III)→Rh(I)→Rh(III) catalytic cycle was proposed for this reaction.

Ruthenium-catalyzed regioselective C2 alkenylation of indoles and pyrroles via C-H bond functionalization.

An efficient ruthenium-catalyzed oxidative coupling of indoles and pyrroles with various alkenes at the C2-position assisted by employing the N,N-dimethylcarbamoyl moiety as a directing group is reported. The catalytic reaction proceeds in an excellent regio- and stereoselective manner.