Rhodium-or Nickel-catalyzed Asymmetric Hydrogenation Of ?,?-unsaturated Carbonyl Compounds

In past decades,great progress has been made in transisiton metal catalyzed asymmetric hydrogenation,and it has been one of the most-used and effective approach to synthesize enantiomerically pure compounds.However,there are some challenges in this filed,for example,asymmetric hydrogenation of?,?-unsaturated carbonyl compounds was dominated by Iridium,however,rhodium complexes,the most frequently used catalyst in asymmetric hydrogenation,has poor performance on asymmetric hydrogenation of?,?-unsaturated carbonyls.Therefore,the development of Rh-catalyzed asymmetric hydrogenation of exocyclic?,?-unsaturated carbonyl compounds is a challenge.In addition,asymmetric hydrogenation is dominated by noble transition-metals,which unvoidable to suffer form some drawbacks,such as high cost and poisinous.Comparatively,cheap transition metal catalyzd asymmetric hydrogenation is rarly reported,thus it's highly desirable to exploit cheap metal catalyzed asymmetric hydrogenation.To solve the above-mentioned problems,Rh-and Ni-catalyzed asymmetric hydrogenation of?,?-unsaturated carbonyl compounds have been investigated in this thesis,and the first Rh-catalyzed asymmetric hydrogenation of exocyclic?,?-unsaturated carbonyl compounds and Ni-catalyzed asymmetric hydrogenation of?-acetylamino-?,?-unsaturated ketones were achieved.The main contents are as follows:(1)The asymmetric hydrogenation of exocyclic?,?-unsaturated carbonyl compounds has been achieved by employing Rh-Zhao Phos as catalyst,giving?-chiral lactone,?-chiral lactam and?-chiral ketone with high chemoselectivity.The synthetic utility of this methodology was demonstrated by a concise synthetic route to chiral piperidines,which obtained though reduction of?,?-unsaturated lactam with Li Al H₄.(2)A preliminary study on Ni-catalyzed asymmetric hydrogenation of?-acetylamino-?,?-unsaturated ketone has been carried out,and chiral 1,3-aminoalcohol was obtained in good yield and high enantioselectivity,but the diastereoselectivity is poor.The related investigations are underway.