Asymmetric Hydrogenation Of ?-ketosulfone And 4-substituted Chroman

Chirality plays an important role in our daily life,so the synthesis of chiral compounds by asymmetric catalysis has become popular among the research.In these studies,asymmetric hydrogenation via transition metals is one of the most efficient and direct method to attain chiral compounds.So we decide to conduct two studies as follows based on what has been developed by our team.(1)In this paper,the asymmetric catalytic hydrogenation of the carbonyl group of?-ketosulfone was carried out by[Ir(COD)Cl]₂/DTB-f-amphol.The catalyst can cause good activity for?-ketosulfone,which can achieve a high yield and enantioselectivity(up to 99%yield and>99%enantioselectivity,and the TON can reach 20000).(2)In this paper,Rh(NBD)₂BF₄/Zhaophos was used to conduct the asymmetric catalytic hydrogenation of?,?-unsaturated Carboxylates with chromophore structure.Firstly,we found that reaction could not take place with substrates of?,?-unsaturated carboxylic acid ester containing benzo pentacyclic.Secondly,groups on the benzene ring could cause big impact on the reaction.Nevertheless,the yield and enantioselectivity of the reaction can reach 99%and 98%,and the TON can reach5000.