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Tridentate pincer ligand can be provided with the metal complex to form a stable complex structure , having a good stability , reactivity and stereoselectivity . Since the 1970s , these compounds in the synthesis, structure , reaction performance and its applications has made significant progress , is widely used in the field of coordination chemistry , organic synthesis , homogeneous catalysis and functional materials , also become a focus for researchers . The nitrogen-containing tridentate ligands and the metal bit ability easily be adjusted by changing the structure of the central metal and the ligand to its catalytic activity and selectivity . Tridentate pincer chiral ligands based philosophy , the main job of the following two parts : 1 . (R)-BINOL chiral source , design and synthesis of two kinds with the axis of chiral binaphthyl group containing nitrogen tridentate pincer the chiral ligands NCN type (L1) and NNN -type ligand (L2). Which , L1 has not been reported . Nitrobenzaldehyde with nitromethane asymmetric Henry reaction as a model reaction to study the catalytic performance of NNN type chiral tridentate pincer ligand L2 with metal salts in situ complexation formed . The optimized reaction conditions : 10 mol% CuOTf/L2 , methanol as a solvent , the reaction at room temperature for 5 days, in 59% yield , 80 ? The amount of alkali added to the catalytic system , the reaction speed ee values ??decreased slightly ; When an organic base ( Me3Si ) joining the large steric hindrance 2MeN , the reaction at room temperature for 17 h, the yield of 37% , an EE value 67 % . This catalytic system is applicable to most of the aromatic aldehydes yield moderate enantioselectivity up to 75 % .
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