Synthesis Of N-Aryl-N'-(4, 12)-Disubstituted [2.2]Paracyclophanyl Dihydroimidazolium Salts

During the past two decades,the synthesis of enantiomerically pure or enriched compounds has emerged as one of the most important fields in organic synthesis. Several procedures to generate optically active molecules are known,and among these,asymmetric catalysis plays an important role and is a highly active research area.The paracyclophane shows striking characteristic with the planar chirality.By introducing the heteoratom,such as phosphor,nitrogen,oxygen and sulphur into paracyclophane,the paracyclophane-based chiral complexs formed with transitional metals already display good stereoselectivity in catalyzing asymmetric synthesis reaction.A series of novel complexes derived from planar chiral paracyclophane and N-heterocyclic carbene reveal much special character that is different from neither the paracyclophane nor the N-heterocyclic carbene.Thus,the research of these novel complexes will have significant and profound meaning for the development of asymmetric catalyst and asymmetric catalytic reaction.This paper is consisted of nine parts:The first part is preparation of[2.2]paracyclophane.Para-methylbenzylammonium chloride reacted with sodium hydroxide at 80-90℃to produce [2.2]paracyclophane.The second part is preparation of 4,12-dibromo[2.2]paracyclophane. 4,16-dibromo[2.2]paracyclophane was obtained by bromination of[2.2]paracyclophane using iron as catalyst,and a suspension of 4,16-dibromo[2.2]paracyclophane in dodecane was heated at 216℃for 20h to afford 4,12-dibromo[2.2] paracyclophane. The third part is preparation of 4-benzophenone imino-12-bromo[2.2]paracyclophane. It was obtained by treatment of 4,12-dibromo[2.2]paracyclophane with benzophenone imine,sodium tert-butoxide and Pd-DPPF.The forth part is preparation and resolution of 4-amino-12-bromo[2.2]paracyclophane. It was hydrolyzed with HCl in THF to furnish exclusively 4-amino12-bromo [2.2]paracyclophane.The fifth part is preparation of Rp-(+)-4-amino-12-(2-methoxyphenyl) [2.2]paracyclophane.It was obtained by Suzuki cross coupling with 2-methoxyphenyl boronic acid under Pd-DPPF catalysis.The sixth part is preparation of Rp-(+)-N,N'-bis{12-(2-hydroxyl phenyl)-4-[2.2] paracyclophane} ethylene-1,2-diamine.Rp-(+)-N,N'-bis{12-(2-methoxyl phenyl) -4-[2.2]paracyclophane}glyoxal diimine was obtained by treatment Rp-(+)-4-amino-12-(2-methoxyphenyl)[2.2]paracyclophane with glyoxal,then it was reduced to the diamine with sodium borohydride.Rp-(+)-N,N'-bis{12-(2-hydroxy phenyl)-4-[2.2]paracyclophane}ethylene-1,2-diamine was obtained from Rp-(+)-N,N'-bis{12-(2-methoxyphenyl)-4-[2.2]paracyclophane}ethylene-1,2-diamine by demethanation with HBr in acetic acid at 114℃for 5h.The seventh part is preparation of Rp-(-)-N-Ar-N'-(12-bromo-4-[2.2]paracyclophane) ethylene-1,2-diamine.Starting from oxalyl chloride and aromatic amines, oxo-arylamino acetyl chlorides were obtained,and then reacted with 4-amino-12bromo [2.2]paracyclophane to produce Rp-(-)-N-Ar-N'-(12-bromo-4-[2.2]paracyclo phanyl)oxamide.Next,the oxamide was reduced by borane to give Rp-(-)-N-Ar-N'-(12-bromo-4-[2.2] paracyclophanyl)ethylene-1,2-diamine.The eighth part is preparation of Rp-(+)-N-Ar-N'-(12-R-4-[2.2]paracyclophanyl) ethylene-1,2-diamine.Under Pd-DPPF catalysis,it was obtained by Suzuki cross coupling with 2-methoxy-phenyl boronic acid,andα-naphthyl boronic acid, respectively.The ninth part is preparation of the new chiral dicyclophane dihydroimidazolium tetrafluoroborates.They were gained from the diamine,triethyl orthoformate and ammonium tetrafluoroborate.The innovation of this thesis is as follows:1.Five novel diamine compounds were obtained.2.Five novel dihydroimidazolium tetrafluoroborates were obtained.