Synthesis And Application Of Chiral 1,1'-spirobiindane Backbone Quaternary Ammonium Salts As Phase-transfer Catalysts

Chiral phase-transfer catalysis is an important branch of organic small molecule catalysis,and play a vital role in asymmetric catalytic synthesis.After more than the past three decades,more than ten kinds of different backbone phase-transfer catalysts has been developed and successfully used in asymmetric organic synthesis and given many products with high stereoselectivity product.Among phase-transfer catalysts chiral quaternary ammonium salts were used widely because of their simple synthesis operation,stabilization and easily modification.Chiral catalyst as a decisive factor in stereoselectivity,development of catalysts is still the frontier and hot spot in asymmetric catalysis field.C₂-symmetric chiral spiro-ligands has exhibited high catalytic performance in transition-metal catalyzed asymmetric reactions,and have been viewed as a class of privileged structure,however,C₂-symmetric chiral quaternary ammonium salt containing1,1'-spirobiindane has not been reported to date.Therefore,development of chiral1,1'-spirobiindane phase transfer catalysts and to test their catalytic performance are also significant.In this thesis,we firstly reviewed the research progress of chiral phase-transfer catalysts,and then,a novel tetramethyl-1,1'-spirobiindane based chiral quaternary ammonium salts as phase transfer catalysts has been developed,and their catalytic performance in asymmetric alkylation of glycinate Schiff base has also been tested.The details information are showed as follows:1.Firstly,commercially available bisphenol A as start material underwent acid-catalyzed arrangement cyclization to deliver rac-tetramethyl-1,1'-spirobiindane-6,6'-diol.Subsequently,a chiral resolution was conducted to give optical purity(R)-enantiomer(>99%ee).Then,Friedel-Crafts reaction,Duff reaction,retro-Friedel-Crafts reaction,trifluoromethane sulfonylation reaction,Suzuki-Miyaura coupling reaction,reduction reaction,bromination reaction and salt forming reaction were performed sequentially,and 16 new chiral tetramethyl-1,1'-spirobiindane quaternary ammonium salts were synthesized successfully in12 steps from bisphenol A with 22-25%total yields.The absolute configuration of catalysts2.9c and 2.9n was confirmed by X-ray and recognized as“R”,and their dihedral angles are65.3°and 64.5°,respectively.2.The catalytic performance of our catalysts were tested in asymmetric alkylation of glycinate Schiff base.After,screening the catalysts,solvents,temperature and bases,a optimum reaction condition was established.Ten optically purity alkylation products of glycinate Schiff base were obtained in high yields(up to 92%)with high enantioselectivities(up to 98%ee)at 2 mol%loading of catalyst 2.9n in toluene using Cs OH·H₂O as base at-60?.Gram-scale reaction of glycinate Schiff base with benzyl bromide under 1 mol%loading of catalyst 2.9n,also delivered the product with high yield and enantioselectivity(84%yield,94%ee).By comparing chiral spirobiindane quaternary ammonium salts phase-transfer catalysts with binaphthyl-based“Maruoka catalyst”in their synthesis routes and catalytic performance in alkylation of glycinate Schiff base.This type of chiral spirobiindane quaternary ammonium salts PTCs is expected to be a complement and alternative to“Maruoka PTCs”in some reactions.