Asymmetric Hydrogenation Of Enamides And ?,?-unsaturated Carbonyl Compounds

Chiral transition metal complexes-catalyzed asymmetric hydrogenation and its application are the hotspots and frontiers of organic chemistry research.A large number of research papers and patents are published every year.Among them,the rhodium-catalyzed asymmetric hydrogenation of functionalized enamides and olefins is characterized by its high yield,high enantioselectivity,atom economy and minimal environmental impact.So this method is better than others for promoting the development of green chemistry.Whether it is catalyzed hydrogenation of enamides to prepare chiral amines or asymmetric reduction of ?,?-unsaturated carbonyl compounds,to prepare various optically active carboxylic acid esters,amides and ketones,the purpose is to obtain a wide range of chiral fragments which can be found in natural products and drugs.And the valuable products will be synthesized through this green and economic method.So the study of transition metal catalyzed asymmetric hydrogenation focuse on the development of more useful catalysts,more moderate reaction conditions and a wider range of substrates.The ultimate goal is to improve the yield and the enantioselectivity.Herein,two new kinds of substrates are designed and applied in Rhodium-catalyzed asymmetric hydrogenation for the preparation of the corresponding chiral amines with high yields and enantioselectivities.And,by introducing a hydrogen bonding of substrates with thiourea from the ligand,?,?-unsaturated carbonyl compounds,such as amides,esters and ketones,are hydrogenated with high enantiomeric excess.The research contents are as follows:1.An efficient and highly enantioselective catalytic asymmetric hydrogenation of?-acetylamino acrylosulfones has been realized by using the Rh-TangPhos as catalyst.A series of chiral ?-amino sulfones products,which are versatile intermediates in organic synthesis,are obtained with high yield and excellent enantioselectivity.And the Julia-Lythgoe olefination of chiral P-amino sulfones can be utilized to generate various kinds of chiral allylic amines,which have been recognized as versatile building blocks for the preparation of biologically important organic derivatives.2.The introduction of trifluoromethyl groups into organic molecules can substantially modify the lipophilicity,metabolic stability and bioavailability of the biologically interesting molecules.Therefore,the chiral trifluoromethyl can replace the chiral methyl for changing the activity of drugs.Highly enantioselective catalytic asymmetric hydrogenation of a-CF3-enamides has been achieved by employing Rh-DuanPhos as the catalyst.This reaction afford corresponding chiral amines in high yields and excellent enantioselectivities(up to 99%ee).3.Highly efficient asymmetric hydrogenation of ?,?-unsaturated carboxylic acid esters,amides and ketones by using the Rh-ZhaoPhos as catalys can achieve a variety of optically active carbonyl compounds with high yields and excellent enantioselectivities.The method utilizes one ligand to achieve the hydrogenation of a variety of unsaturated carbonyl compounds through the cooperation of transition metal catalysis and organocatalysis.