A silylated PNP ligand with asymmetric structure was synthesized using(γ-aminopropyl)triethoxysilane and chlorodiphenyl phosphine as raw materials.The optimal synthetic conditions of the PNP ligand were obtained by c...A silylated PNP ligand with asymmetric structure was synthesized using(γ-aminopropyl)triethoxysilane and chlorodiphenyl phosphine as raw materials.The optimal synthetic conditions of the PNP ligand were obtained by conditional experiments and were as follows:dichloromethane was solvent,triethylamine was acid acceptor,the mole ratio of chlorodiphenylphosphine and(γ-aminopropyl)triethoxysilane was 2.1∶1,the dropping temperature of chlorodiphenylphosphine was-5℃,the dropping time was 30 min,the reaction temperature was 25℃and the reaction time was 12 h.Under the conditions,the yield of the silylated PNP ligand was 91.20%.Based on grey correlation analysis,the dropping temperature was the main factor for the yield of the silylated PNP ligand.The single-active central chromium catalyst based on the silylated PNP ligand was synthesized by complexation reaction with the silylated PNP ligand and chromium chloride tetrahydrofuran complex as materials,and the yield was 95.25%.The chemical structures of the silylated PNP ligand and the corresponding chromium catalyst were confirmed by elemental analysis,FT-IR,^(1)H NMR,MS and ICP.The single-active central chromium catalyst based on the silylated PNP ligand had good catalytic activity for ethylene oligomerization,and the content of C_(8)olefin was 72.40%,which was superior to Si-Schiff-Cr based on intermolecular coordination.展开更多
Asymmetric hydrogenation of dialkyl imines to chiral amines is difficult because the two alkyls of imines are so similar in spatial and electronic structure that chiral catalysts are difficult to distinguish between t...Asymmetric hydrogenation of dialkyl imines to chiral amines is difficult because the two alkyls of imines are so similar in spatial and electronic structure that chiral catalysts are difficult to distinguish between them.In this study,we described an asymmetric hydrogenation of dialkyl imines by a chiral iridium catalyst containing spiro phosphine-amine-phosphine ligand.By precisely adjusting the chiral pocket of catalyst,a highly efficient catalyst was developed.Using this catalyst,a variety of dialkyl imines were hydrogenated to chiral amines with high yield and enantioselectivity.展开更多
This work detailed the preparation of a class of water-soluble PNP ligands that differed by the nature of the substitute on phenyl ring of ligands. These ligands were incorporated into water-soluble rhodium-PNP comple...This work detailed the preparation of a class of water-soluble PNP ligands that differed by the nature of the substitute on phenyl ring of ligands. These ligands were incorporated into water-soluble rhodium-PNP complex catalysts that were used to regioselective hydroformylation of a series of terminal arylalkenes,providing efficient access to rac-α-aryl propionaldehydes in good to excellent yield(up to 97%) and branched-regioselectivity(up to 40:1 b/l ratio). Furthermore, gram-scale and diverse synthetic transformation demonstrated synthetic application of this methodology for non-steroidal antiinflammatory drugs.展开更多
基金supported by Key Research and Development Project of Heilongjiang Province(JD22A026)
文摘A silylated PNP ligand with asymmetric structure was synthesized using(γ-aminopropyl)triethoxysilane and chlorodiphenyl phosphine as raw materials.The optimal synthetic conditions of the PNP ligand were obtained by conditional experiments and were as follows:dichloromethane was solvent,triethylamine was acid acceptor,the mole ratio of chlorodiphenylphosphine and(γ-aminopropyl)triethoxysilane was 2.1∶1,the dropping temperature of chlorodiphenylphosphine was-5℃,the dropping time was 30 min,the reaction temperature was 25℃and the reaction time was 12 h.Under the conditions,the yield of the silylated PNP ligand was 91.20%.Based on grey correlation analysis,the dropping temperature was the main factor for the yield of the silylated PNP ligand.The single-active central chromium catalyst based on the silylated PNP ligand was synthesized by complexation reaction with the silylated PNP ligand and chromium chloride tetrahydrofuran complex as materials,and the yield was 95.25%.The chemical structures of the silylated PNP ligand and the corresponding chromium catalyst were confirmed by elemental analysis,FT-IR,^(1)H NMR,MS and ICP.The single-active central chromium catalyst based on the silylated PNP ligand had good catalytic activity for ethylene oligomerization,and the content of C_(8)olefin was 72.40%,which was superior to Si-Schiff-Cr based on intermolecular coordination.
基金supported by the National Key R&D Program of China(grant no.2022YFA1504302)the National Natural Science Foundation of China(grant nos.22188101,91956000,and 92256301)the Fundamental Research Funds for the Central Universities,and the Haihe Laboratory of Sustainable Chemical Transformations.
文摘Asymmetric hydrogenation of dialkyl imines to chiral amines is difficult because the two alkyls of imines are so similar in spatial and electronic structure that chiral catalysts are difficult to distinguish between them.In this study,we described an asymmetric hydrogenation of dialkyl imines by a chiral iridium catalyst containing spiro phosphine-amine-phosphine ligand.By precisely adjusting the chiral pocket of catalyst,a highly efficient catalyst was developed.Using this catalyst,a variety of dialkyl imines were hydrogenated to chiral amines with high yield and enantioselectivity.
基金financial support from the National Natural Science Foundation of China (No.21902032)。
文摘This work detailed the preparation of a class of water-soluble PNP ligands that differed by the nature of the substitute on phenyl ring of ligands. These ligands were incorporated into water-soluble rhodium-PNP complex catalysts that were used to regioselective hydroformylation of a series of terminal arylalkenes,providing efficient access to rac-α-aryl propionaldehydes in good to excellent yield(up to 97%) and branched-regioselectivity(up to 40:1 b/l ratio). Furthermore, gram-scale and diverse synthetic transformation demonstrated synthetic application of this methodology for non-steroidal antiinflammatory drugs.
