Copper(Ⅱ)-catalyzed Enantioselective Intramolecular Diamination Of Alkenes And Palladium-catalyzed Intramolecular Amidation/Oxidation Of Imines

Chiral vicinal diamine-containing heterocycles moiety are commonly encountered innatural products and biologically active pharmaceutical molecules. These compounds havebeen widely used in coordination chemistry、Guest-Host chemitsty and asymmetric catalysis.Among the different vicinal diamines, benzoimidazoles have also attracted increasingattention in the field of photoelectric materials, new-type resin and ion-liquids, et al.Therefore, developing efficient synthetic method to highly enantioselective and regioselectiveassemble of vicinal diamino derivatives is of great significance.The dissertation comprises two parts involving synthesis of vicinal diamines.At first, transition-metal Cu(II)/(I)、Pd(II)、Ni(II) and Au(I) have been developed to catalyzeintramolecular diamination of alkenes and quickly assemble of vicinal diamine-containingheterocycles, but transition-metal-catalyzed intramolecular enantioselective diamination ofolefins has not achieved any breakthrough up to now. We report here the first Cu(II)-catalyzed asymmetric intramolecular diamination of alkenes. Detailed and systematicoptimization of this transformation showed that Cu(OTf)2(35mol%)/(4R,4’R)-2,2’-(1-Methylethylidene)bis(4,5-dihydro-4-phenyloxazole)(45mol%)/Li2CO3(2.0equiv)/MnO2(3.0equiv) reaction system could catalyze enantioselective intramolecular diaminationof unactivated alkenes in moderate to good yields (up to86%) with high to excellentenantioselectivity (up to98%ee). The investigation of the substrate scope about thistransformation demonstrated broad functional group compatibility. More importantly, thereaction could still furnish the chiral quaternary carbon-containing diamination products. Theabsolute configuration of the diamination product was determined to be S through the X-raycrystallographic analysis. Further synthetic application of asymmetric diamination productscould afford other type of chiral vicinal diamines with the enantioselectivity retained.On the other hand, development of novel methods for the preparation of benzoimidazolescontinues to be a hot topic of organic chemistry. Based on the Cu(II)-catalyzedintermolecular amidation of C-acylimine from our group, we continued to investigate Pd(II)-catalyzed intramolecular amidation of imines which could lead to formation of1,2- disubstituted benzoimidazoles. Reaction condition optimizing about this transformationindicated that PdCl2(10mol%)/PhI(OAc)2(2.0equiv)/K2CO3(2.0equiv) catalytic systemcould realize intramolecular amidation of imines to produce multisubstituted benzoimidazolesin moderate to excellect yield. Expanding the substrate scope showed broad functional groupcompatibility, regardless of electron-deficient group and electron rich group at phenyl rings.This strategy provides a concise access to2-alkyl、2-aryl、2-alkenyl、2-acyl and2-esterfunctional group-substituted benzimidazoles under mild conditions. It is worth noting thatO-sulfonamidophenylimines could not only undergo intramolecular sulfonamidation/ox-idation cyclization reaction, but also provided free1H-2-substituted benzoimidazole via aone-pot desulfonylation.