Synthesis And Application Of Precursor Of N-Substituted Planar Chiral N-Heterocyclic Carbene

A remarkable characteristic of paracyclophane is of planar chirality.Being of chiral source,it has attracted great research interests to chemists.By introducing the heteroatoms,such as phosphor,nitrogen,oxygen,and sulphur into paracyclophane, the chiral paracyclophane-based complexes formed with transition metals,already displayed good catalytic effect in asymmetry synthesis and reaction.Imidazoliums and imidazoliniums,the precursors of N-heterocyclic carbenes,combined with transition metals have been used to catalyze the reaction of forming C-C,C-H,C-O, C-N,and olefin metathesis.Due to the special properties of paracyclophane-based N-heterocyclic carbenes,the new complexs will offer lots of character which differ from either the paracyclophane or the N-heterocyclic carbenes.Therefore,the research of chiral paracyclophane-based N-heterocyclic carbenes has significant and profound meaning in developing the asymmetric catalyst and the asymmetric catalytic reaction.The primary content of this thesis has nine parts:The first part is preparation of[2.2]paracyclophane.At 80-90℃in DMSO,para-methylbenzyl(N,N,N-trimethyl)ammonium chloride reacted with sodium hydroxide to produce[2.2]paracyclophane.The second part is preparation of 4,16-dibromo[2.2]paracyclophane.4,16-Dibromo[2.2]paracyclophane was obtained by bromination of[2.2] paracyclophane using iron as catalyst.The third part is preparation of 4,12-dibromo[2.2]paracyclophane.4,16-Dibromo[2.2]paracyclophane in dodecanese was heated at 230℃to attain 4,12-dibromo-[2.2]paracyclophane.The fourth part is preparation and resolution of 4-amino-12-bromo[2.2] paracyclophane. 4-Dibenzophenone imino-12-bromo[2.2]paracyclophane was obtained by treatment of 4,12-dibromo[2.2]paracyclophane with benzophenone imine,in the presence of sodium tertbutoxide and Pd-DPPF catalyst.Then it is hydrolyzed by HCI in THF to give 4-amino-12-bromo[2.2]paracyclophane.The resolution of 4-amino-12-bromo[2.2] para cyclophane was achieved to produce R_p-(-)-4-amino- 12-bromo[2.2] paracyclophane.The fifth part is preparation of R_p-(-)-N,N'-bis(4-[2.2]Paracyclophany -12- bromo) ethylene-1,2-diamine.4-Amino-12-bromo[2.2]paracyclophane reacted with glyoxal to give R_p-(-)- N,N'-bis (4-bromo-12-[2.2]paracyclophanyl)glyoxal diimine,followed by reduction with sodium borohydride.The six part is preparation of R_p-(-) - N,N'-bis(4-dibenzophenone imino-12-[2.2] ethylene-1,2-diamine and R_p(+)-N-12-bromo-4-[2.2]paracyclophanyl) - N'-(12-dibenzophenoneimino-4-[2.2]paracyclophanyl)ethylene-1,2-diamine.They were obtained by treatment of 4,12- dibromo[2.2]paracyclophane with dibenzophenone imine,sodium tertbutoxide and Pd-DPPF catalyst.The seven part is preparation of R_p(+)-N-(12-R-4-[2.2]paracyclophanyl ) -N'-(12-dibenzophenone imino-4-[2.2]paracyclophanyl)ethylene-1,2-diamine.Under Pd-DPPF catalysis in dioxane,R_p(+)-N-(12-bromo-4-[2.2]paracyclophanyl) -N'-(12-dibenzophenoneimino-4-[2.2]paracyclophanyl)ethylene-1,2-diamine reacted with 2-methoxyphenyl boronic acid and 3-methoxyphenyl boronic acid,respectively, to gived the desired compounds in good yields.The eight part is preparation of dihydroimidazolium tetrafluoroborates.R_p(-)-N-(12-R-4-[2.2]paracyclophanyl)-N'-(12-dibenzophenone imino-4-[2.2] paracyclophanyl)-4,5-dihydroimidazolium tetrafluorborates were gained from the triethyl orthoformate and ammoniums tetrafluoroborate.The ninth part is preparation of imidazolium trifluoromethanesulfonateIt was obtained from R_p-N,N'- bis(12-dibenzophenone imino-4-[2.2] paracyclophane) glyoxal diimine,chloromethyl pivalate and silver trifluoromethanesulfonate. The tenth part is preparation of asymmetric imidazolium trifluoromethanesulfonate R_p-(+)-4- amino -12-R-[2.2]paracyclophane were gained by Suzuki reaction,then react with 2,4,6-trimethyl phenyl glyoxal diimine,chloromethyl pivalate and silver trifluoromethanesulfonate.The eleventh part is catalytic research:Rhodium-catalyzed asymmetric 1,2-addition of arylboronic acids to aldehydesThe innovation of this thesis is as follows:1.Five novel N-substituted planar chiral imidazoliniums were synthesized.2.The five new precursors of N-heterocyclic carbene were used as ligands for Rhodium-catalyzed asymmetric 1,2-addition of arylboronic acids to aldehydes.