Many trifluoromethoxylation approaches often proposed nucleophilic (AgOCF3)-O-I as a key intermediate. However, the structure of this intermediate remains elusive. Herein, the thermally stable, light-insensitive nucleophilic trifluoromethoxylating reagent [Ag((PPhBu2)-Bu-t)(OCF3)] (1) was prepared and fully characterized. Reagent 1 reacted with a variety of alkyl electrophiles including benzyl bromodes/chlorides, primary alkyl bromides/iodides/triflates/nosylates, and secondary alkyl bromides/triflates/nosylates in good to excellent yields. Mechanistic investigation by reaction with three enantioenriched secondary alkyl electrophiles suggested that these reactions proceed via an S(N)2 pathway, which is consistent with our original mechanistic hypothesis.

Rhodium(III)-catalyzed atroposelective C-H selenylation of 1-aryl isoquinolines has been achieved. The direct C-H selenylation reaction between 1-aryl isoquinolines and 2-(phenylselanyl)isoindoline-1,3-dione in the presence of the chiral SCpRh(III) complex afforded a series of axially chiral 1-aryl isoquinoline selenides in up to 95% yield and 96% ee. The reaction features mild conditions and a broad substrate scope. DFT calculations revealed that the C-Se bond formation step proceeds through a formal SN2 pathway.

P-Chiral phosphorus ligands received little attention in organic chemistry until Knowles made his landmark contribution in asymmetric hydrogenation by developing the P-chiral ligands CAMP and DIPAMP. The development of P-chiral phosphorus ligands accelerated in the end of the last century with the advent of some highly efficient and renowned ligands for asymmetric hydrogenation, including BisP*, TangPhos, QuinoxP*, DuanPhos, et al. However, most reported ligands were air-sensitive, difficult to make, or lacked structural modularity, hampering their availability and applicability. The development of sterically and electronically tunable P-chiral phosphorus ligands is particularly desirable. Over the past decade, a family of sterically hindered, electron-rich, structurally tunable, and air-stable P-chiral dihydrobenzooxaphosphole ligands emerged that proved to be efficient and versatile for various asymmetric transformations. The last 5 years witnessed an increasing number of studies related to these ligands with the discovery of their unprecedented catalytic properties in various transformations. This review highlights the unique properties of P-chiral dihydrobenzooxaphosphole ligands in catalysis and their applications in the synthesis of natural products and therapeutic agents.

Catalytic asymmetric alkylation of a -halogenated enolates is a challenging issue due to their extenuated nucleophilicity and the electrophilic and oxidative nature of the parent a-Cl/Br carbonyl compounds. Herein, by means of coordination -stabilized copper(I) a-F/Cl enolates as the nucleophiles, a catalytic asymmetric alkylation of 2-azaarylesters is achieved with a broad substrate scope on alkyl halides, which constructs halogenated tetrasubstituted carbon centers in good to excellent yields with high enantioselectivity. Moreover, the present alkylation protocol is successfully applied in the building of chiral quaternary carbon centers. Finally, synthetic utilities of the products are demonstrated by several facile transformations based on the alkyl chloride group and the ester group.

RationaleThe mechanisms underlying major depressive disorder (MDD) in children and adolescents are unclear. Metabolomics has been utilized to capture metabolic signatures of various psychiatric disorders; however, urinary metabolic profile of MDD in children and adolescents has not been studied.ObjectivesWe analyzed urinary metabolites in children and adolescents with MDD to identify potential biomarkers and metabolic signatures.MethodsHere, liquid chromatography-mass spectrometry was used to profile metabolites in urine samples from 192 subjects, comprising 80 individuals with antidepressant-naive MDD (AN-MDD), 37 with antidepressant-treated MDD (AT-MDD) and 75 healthy controls (HC). We performed orthogonal partial least squares discriminant analysis to identify differential metabolites and employed logistic regression and receiver operating characteristic analysis to establish a diagnostic panel.ResultsIn total, 143 and 71 differential metabolites were identified in AN-MDD and AT-MDD, respectively. These were primarily linked to lipid metabolism, molecular transport, and small molecule biochemistry. AN-MDD additionally exhibited dysregulated amino acid metabolism. Compared to HC, a diagnostic panel of seven metabolites displayed area under the receiver operating characteristic curves of 0.792 for AN-MDD, 0.828 for AT-MDD, and 0.799 for all MDD. Furthermore, the urinary metabolic profiles of children and adolescents with MDD significantly differed from those of adult MDD.ConclusionsOur research suggests dysregulated amino acid metabolism and lipid metabolism in the urine of children and adolescents with MDD, similar to results in plasma metabolomics studies. This contributes to the comprehension of mechanisms underlying children and adolescents with MDD.

Here, we describe a cooperative Pd(0)/chiral phosphoric acid catalytic system that allows us to realize the first chemo-, regio-, and enantioselective sequential cross-[4 + 2]-cycloaddition/decarboxylation reaction between 2-pyrones and unactivated acyclic 1,3-dienes. The key to the success of this transformation is the utilization of an achiral N-heterocyclic carbene (NHC) as the ligand and a newly developed chiral phosphoric acid as the cocatalyst. Experimental investigations and computational studies support the idea that the Pd(0)/NHC complex acts as a pi-Lewis base to increase the nucleophilicity of 1,3-dienes via eta 2 coordination, while the chiral phosphoric acid simultaneously increases the electrophilicity of 2-pyrones by hydrogen bonding. By this synergistic catalysis, the sequential cross-[4 + 2]-cycloaddition and decarboxylation reaction proceeds efficiently, enabling the preparation of a wide range of chiral vinyl-substituted 1,3-cyclohexadienes in good yields and enantioselectivities. The synthetic utility of this reaction is demonstrated by synthetic transformations of the product to various valuable chiral six-membered carbocycles.

Unfractionated heparin (UFH) and low-molecular-weight heparins (LMWHs) are widely applied for surgical procedures and extracorporeal therapies, which, however, suffer bleeding risk. Protamine, the only clinically approved antidote, can completely neutralize UFH, but only partially neutralizes LMWHs, and also has a number of safety drawbacks. Here, we show that caltrop-like multicationic small molecules can completely neutralize both UFH and LMWHs. In vitro and ex vivo assays with plasma and whole blood and in vivo assays with mice and rats support that the lead compound is not only superior to protamine by displaying higher neutralization activity and broader therapeutic windows but also biocompatible. The effective neutralization dose and the maximum tolerated dose of the lead compound are determined to be 0.4 and 25 mg/kg in mice, respectively, suggesting good promise for further preclinical studies.

O-Sulfation is a vital post-translational modification in bioactive molecules, yet there are significant challenges with their synthesis. Dialkyl sulfates, such as dimethyl sulfate and diisopropyl sulfate are commonly used as alkylation agents in alkaline conditions, and result in the formation of sulfate byproducts. We report herein a general and robust approach to O-sulfation by harnessing the tunable reactivity of dimethyl sulfate or diisopropyl sulfate under tetrabutylammonium bisulfate activation. The versatility of this O-sulfation protocol is interrogated with a diverse range of alcohols, phenols and N-OH compounds, including carbohydrates, amino acids and natural products. The enhanced electrophilicity of the sulfur atom in dialkyl sulfates, facilitated by the interaction with bisulfate anion (HSO4-), accounts for this pioneering chemical reactivity. We envision that our method will be useful for application in the comprehension of biological functions and discovery of drugs.