New Chiral Secondary Amine Catalyst: Its Design, Preparation And Properties Of Asymmetric Catalysis

In this dissertation,recent advances in the asymmetric organocatalysis and especially in chiral amine catalyzed such as Lproline and its derivatives and MacMillan imidazolone catalyst were summarized and reviewed firstly.Next,a new class of pyrrolidine-2-ylmethylthio and imidazolone catalyst were designed and prepared. Then Michael reactions of nitro olefin and cyclic ketone in PEG/ Pyrrolidin-2-ylmethylthio sulfide complex system and the Michael-Aldol cascade reaction ofα,β-unsaturated aldehydes and cyclic ketone were studied academically.The Pyrrolidin-2-ylmethylthio compounds were obtained high selectivity from L-proline by reduction,bromide,and sulfide,and there structures were confirmed through NMR,MS and X-ray single crystal diffraction.The Michael reaction of nitroolefin to cyclic ketone in PEG/ pyrrolidine- 2-ylmethylthio complex system,the experimental results show that this complex system have catalytic activity and stereoselectivity.Michael adducts were afforded with good yields(99%), high diastereoselectivities(up to 95/5) and excellent enantioselectivities (up to 98%ee) in MPEG750.The Michael-Aldol cascade reaction ofα,β-unsaturated aldehydes and cyclic ketone was reported for the first time.Imidazolinone catalyst can be a good catalyst for the reaction from our research,then we synthesized some imidazolinone catalyst from L-Phenylalanine and the structures were confirmed by NMR,MS and X-ray single crystal diffraction.The effection of the catalyst system and solvent were studied, in the best of circumstances Michael-Aldol cascade reaction give the products which have four chiral centers and bicyclic skeleton structure with good yields(80%) and excellent enantioselectivities(75%ee).The catalytic system can catalysis a various Michael-Aldol tandem reaction ofα,β-unsaturated aldehydes to ketones.We also research the tandem reaction mechanism and the law of chiral induction,the absolute configuration of the product(1S,2R,4R,5R) was work out by molecular modeling calculation of energy minimization and X-ray diffraction.