Study On Asymmetric Catalysis Of Chiral Diphenyl Ethylenediamine - Ruthenium Catalyst

Chiral alcohols are important building blocks for drug synthesis, which widely used in areas of pesticide, medicinal chemistry and fine chemical industry. An efficient way to obtain these chiral alcohols is through the Asymmetric Transfer Hydrogenation(ATH) of various related ketones. Compared with reduction of ketones through molecular hydrogen, ATH benefits a lot from mild conditions, easy operation and cheap hydrogen source, so it develops rapidly.In the synthesis of chiral compounds which contain several stereo-centers,resolution is a useful method and it is particularly important. As the maximum production rate of traditional kinetic resolution is only 50%, dynamic kinetic resolution was found and has attracted much attention of many chemists later. By adopting the method of dynamic kinetic resolution, theoretically speaking, all racemic substrates can be converted into a single enantiomer, and their theoretical yields are100%, while high ee and dr can be obtained at the same time. Since this technology has been used, researchers have applied this technology to nearly all kinds of chiral products, and they have made great achievements. Based on this, the main research contents of this article is as follows:1 Dual Pathway for ATH of α-Ketoimides to Chiral α-Hydroxy Imides or Chiral α-Hydroxy Esters. We take α-ketoimides as catalytic substrates, and use two similar chiral Ru catalysts in two different reaction conditions in order to get two kinds of chiral products while just through a slight adjustment. The yields of route 1(products are chiral α-alcohol imides) can reach 95%, and ee up to 95%; The yields of route 2(products are chiralα-alcohol esters) can reach 95%, and ee up to 96% ee.2 Dynamic Kinetic Resolution-Asymmetric Transfer Hydrogenation for the Synthesis of 3,4-dihydro-2H-pyran Derivatives. We take the adducts of chalcone derivatives and malononitrile as catalytic substrates, and do DKR-ATH experiments under mild conditions. The yields are in a scope of72-84%, ee from 89% to 99% % and Dr in 80:20-98:2.