Study On Preparation And Application Of Chiral Phosphorus Sulfur Ligands Porous Organic Polymers

Homogeneous catalysts are widely used in organic reactions.Their use makes the separation process complex,and expensive homogeneous catalysts are difficult to recycle,which limits their large-scale use to a certain extent.The heterogeneity of homogeneous catalysts has become an effective way to solve this problem.Porous organic polymers are a new class of polymeric materials with stable molecular skeletons,high modifiability,large specific surface area,well-developed pores,low density and easy separation from solvent systems,which are often used as carriers for multiphase catalysts.Based on the previous work of the research group in the development and application of chiral P,S ligands,we have done the following research on the heterogeneous of such chiral ligands:（1）Design and Synthesis of Vinylated Chiral P,S Ligand MonomersThe first generation of chiral P,S ligands contains phosphoramidite and chiralβ-aminosulfide,and containing phosphoramidite with axial chirality and chiralβ-aminosulfide fragments are second generation chiral P,S ligands.Based on the f first-and second-generation chiral P,S ligands,vinyl was introduced to synthesize vinyl based chiral P,S ligands.At first,the chiral amino alcohol is converted into azacyclopropane through Mitsunobu Reaction,then azacyclopropane is nucleophilic with 4-bromophenylthiophenol,reductively aminated with vinyl aldehydes,and finally forms N-P bond and P-O bond with vinyl phenolic compounds and phosphorus trichloride through electrophilic attack.The first and second generation of vinyl chiral phosphorus-sulfur ligand monomers are successfully synthesized.The structures of the target products were determined by ¹H NMR,¹³C NMR,and ³¹P NMR,and the molecular weights were analyzed by high-resolution mass spectrometry.（2）Synthesis and application of the first generation of chiral P,S ligand porous organic polymersThe vinylated first-generation chiral P,S ligand monomers were polymerized with p-stilbene to obtain first-generation chiral P,S ligand two-component porous organic polymers,which were applied to the palladium-catalyzed[4+2]dipole cycloaddition reactions of vinylbenzoxazinones withα-diazo ketone compounds and nitroolefins,respectively.The results showed that with POP-MBVPS-II and POP-MTVPS-II as ligands,the target products could be obtained in good yields and enantioselectivity,while the reactions hardly occurred when POP-BVPS-II,POP-TVPS-II,POP-BV`PS-II,POP-TV`PS-II were used as ligands.The polymerization of the polymer was relatively high after ¹³C MAS NMR characterization,but the valence state of phosphorus in the polymer was changed by ³¹P MAS NMR characterization.Accordingly,the first-generation chiral phosphorus-sulfur ligand monomer,stilbene and styrene three-component polymers of vinylation were polymerized to obtain the first-generation chiral phosphorus-sulfur ligand three-component porous organic polymer.In the palladium-catalyzed[4+2]dipole cycloaddition reaction of vinylbenzoxazinone withα-diazo ketone compounds and nitroolefins,the target products can be obtained in good yields and enantioselectivity.Especially,the polymer POP-BV`PS-III was recycled five times still with 64%yield and 92%obtained chiral tetrahydroquinoline products,which were tested by¹³C MAS NMR,³¹P MAS NMR,SEM,TEM,TG,etc.（3）Synthesis and application of the second generation of chiral P,S ligand porous organic polymersA three-component porous organic polymer of the second generation of chiral phosphorus-sulfur ligand was prepared by polymerization of vinylated chiral P,S ligand monomer,p-stilbene and styrene.The use of polymers for the copper-catalyzed[3+2]cycloaddition of iminoesters with nitroolefins enables the facile synthesis of polysubstituted chiral pyrrolidines in high yields.The catalyst Pd/POP-S-BVCy PS was prepared using the polymer POP-S-BVCy PS as a carrier,and the catalyst was used in the[8+2]dipole cycloaddition of vinyl oxacarbamate withα-diazo ketone to give decameric lactone compounds in 99%yield,and in the[3+2]dipole cyclization/Cope rearrangement sequence reaction of hexameric cycloalkenyl ketone with vinyl carbonate to give nine-membered cyclic lactone compounds in 40%yield and 97%ee.The structures of porous organic polymers were characterized by ¹³C MAS NMR and ³¹P MAS NMR,and the surface morphology was tested by SEM and TEM,followed by X-ray photoelectron spectroscopy for the P 2p and Pd 3d orbitals of POP-S-BVCy PS and Pd/POP-S-BVCy PS.