Nitrogenous Oxygen Hetero-atom (4,12) - Substituted Ring Imitation Surfaces Of Chiral Nitrogen-containing Heterocyclic Carbene Precursors Of Synthetic Study

The paracyclophane shows striking characteristic with the planar chirality. Being the chiral source, it has caused the strong interest of the chemists more and more. By introducing the heteoratom of phosphor, nitrogen, oxygen, sulphur into paracyclophane, the chiral complexes formed with transition metals, already displayed good stereoselectivity for catalyzing chiral synthesis reaction. Complexes of N-heterocyclic carbehes with transition metals have been developed to catalyze the formation of the C-C, C-H, C-O and C-N .The chiral paracyclophanes were introduced to the N-heterocyclic carbenes, it would be afford a type of new chiral ligands. New complexes formed by treatment of transition metals with these chiral ligands, will offer a lot of special character neither differ from the paracyclophanes nor differ from the nitrogen heterocyclic carbenes. The research of N-heterocyclic carbenes beraing chiral paracyclophanes, for development the asymmetric catalyst and the asymmetric catalytic reaction ,have the significant and profound meaning.Experiment of this paper consists ten parts, the general are as follows:The first part is preparation of [2,2]paracyclophane. Paramethylbenzylammonium chloride reacts at 70-80℃ with the phenothiazine, potassium borohydride and sodium hydroxide to produce [2,2]paracyclophane.The second part is preparation of 4,X- dibromo-[2,2]paracyclophane which is obtained by bromination of [2,2]paracyclophane with iron catalyst. .A suspension of 4,16-dibromo[2,2]paracyclophane in coal oil is heated at 230℃ for 3 hours to afford 4,12-dibromo[2,2]paracyclophane.The thrid part is preparation of 4-benzophnonimine-X-bromo [2,2]paracyclo phane which is obtained by treatment of 4,12-dibromo[2,2]paracyclophane with benzophenone imine, sodium tert-butoxide and Pd-DPPFcatalyst.The forth part is preparation and resolution of 4-amino-12-bromo[2,2]paracyclo phane, which is hydrolyzed with HCL in THF to furnish exclusively 4-amino-12-bromo[2,2]paracyclophane.The fifth part is preparation of Rp-4-amino-12-R-[2,2] paracyclophane which is obtained by Suzuki cross coupling with 2-methoxyphenyl boronic acid and a-naphthyl boronic acid under Pd-DPPF catalysis.The sixth part is that Rp-4-amino-12-bromo-[2, 2] paracyclophane was mixed with acetic anhydride, acetic acid and solid sodium nitrite, followed by hydrolysis with passium hydroxide to give Rp-4-hydroxy-12-bromo-[2,2]paracyclophane. Rp-4-methoxy -12-bromo-[2, 2] paracyclophane can be readily accessed from Rp-4-hydroxy -12-bromo-[2, 2] paracyclophane, dimethyl sulphate and passium carbonate as base.The seventh part is that diimines were obtained by treatment with glyoxal, which was reduced to the diamine with sodium borohydride.The eighth part is that new symmetrical dicyclophane dihydroimidazolium tetrafluoroborates were gained from the diamine, triethyl orthoformate and ammonium tetrafluoroborate.The ninth part is preparation of imidazoliums. By using poly aldehyde, trifluoromethyl sulfonic sliver and chloromethyl ethyl ether, and chloromethyl methyl ether as closing ring reagent, respectively, products were obtained in unsatisfied yield.Innovation of the paper:First, we employ several different Pd resourses and ligands, and finally find the auto- catalysis of 4,12-dibenzophnonimine- [2,2]paracyclophane.Second, we got several new dihydroimidazolium tetrafluoroborates.