Research Of Rhodium And Copper-catalyzed Asymmetric Addition Reaction

With the increasing recognition of the chiral compounds, the study on the asymmetric synthesis of chiral compounds by metal catalyst is also becoming more closely.The design of new chiral ligands,which is more efficient and more broadly applicable, plays a central role in asymmetric catalysis.In this paper, we mainly studied thedesignand synthesis ofnew chiral ligands and the Rh、Cu-catalyzed asymmetric addition reactionsIn the first part, on the basis of the works of Bis-oxazoline(BOX) which is widely used in asymmetric catalytic reactions, we replaced one of the oxazoline ring to olefin structure and proposed three types of olefin-oxazoline(OlefOx) ligands by three strategies: changing the rigidity of the backbone、adjusting the carbon chain between the oxazoline ring and the olefinstructureandchanging the position of the chiral center. This 20 olefin-oxazoline(OlefOx) ligands’ s application in asymmetric 1,4-addition reaction of arylboronic acid to cyclohexone/ cyclopentenone to test the reactivity of each ligand. At last the good or excellent yield and >90% ee values were successfully achieved.In the second part, we first redesign and optimize the synthesis of the N-Hetero-cyclic carbenes(NHCs) which has been reported. During the optimization, we developed a class of chiral NHCs bearing imidazolidinylidene skeleton, it features two difference kinds substituent on the nitrogen atoms, one is alkyl and the other is aryl(typically the two substituents are either aryl or alkyl). Finally, we have successfully applied these NHCs in the copper catalyzed addition of B2Pin2 to N-benzoyl imine and with the enantiomeric excess up to 84%.It is the first enantioselective synthesis of α-amido boronic esters which is determined by the chiral catalyst.In the third part,we first design and synthesis a series of enone diones with the structures of allene and 1,3-Cyclo-dikeone.The diastereoselective copper-catalyzed domino conjugate boration/ intramolecular cyclization of enone diones and B2Pin2 or B2nep2 to give different kinds of polycyclic products. The cheap achiral Phosphorus ligand can provided the good results(yield>80%, d.r.>20:1),but when we use the chiral ligand,only furnished products with highdiastereoselectivities(>20:1) and low enantioselectivities(up to 53% ee).In the last part, on the basis of our group’ studies, we have studied copper-catalyzed asymmetric allylation of chiral N-tert-butanesulfinyl imines, including aldimines and ketimines, with allylboronic acid pinacol ester has been successfully established.This reaction proceeded smoothly at room temperature, affording optically active homoallylic amines with excellent yields(90-99%) and diastereoselectivities(all d.r. > 99:1).Notably, ketimine substrates, through the matched dual stereocontrol from chiral auxiliary and chiralcopper complex,could also provide nearly perfectdiastereoselectivity.