Publications by authors named "Yongan Yuan"

Direct C-H trifluoromethylation of heterocycles is a valuable transformation. In particular, nonprecious metal-catalyzed C-H trifluoromethylation processes, which do not proceed through CF radical species, have been less developed. In this cluster report, a new copper-catalyzed aerobic C-H trifluoromethylation of phenanthrolines is described.

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Reported herein is a new iron-catalyzed diastereoselective olefin diazidation reaction which occurs at room temperature (1-5 mol% of catalysts and d.r. values of up to >20:1).

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An enantioselective intramolecular indole aminohydroxylation reaction is catalyzed by iron(II)-chiral bisoxazoline (BOX) complexes (ee up to 99%, dr > 20:1). This discovery enables expedient asymmetric synthesis of a series of biologically active 3-amino oxindoles and 3-amino indolanes.

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A diastereoselective aminohydroxylation of olefins with a functionalized hydroxylamine is catalyzed by new iron(II) complexes. This efficient intramolecular process readily affords synthetically useful amino alcohols with excellent selectivity (dr up to > 20:1). Asymmetric catalysis with chiral iron(II) complexes and preliminary mechanistic studies reveal an iron nitrenoid is a possible intermediate that can undergo either aminohydroxylation or aziridination, and the selectivity can be controlled by careful selection of counteranion/ligand combinations.

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In the research work, "click" chemistry was used to modify waterborne polyurethane (WPU) with silane coupling agent (SiCA) functionalized nano-silica. The modified WPU (CWPU) was characterized by FTIR, scanning electron microscope (SEM), thermogravimetric analysis (TGA) and contact angle measurement. The experiment results show that the modification can improve the thermal stability, hardness, and water or weather resistance of CWPU.

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