Synthesis And Application Of Chiral Alkene And Alkene-hybrid Ligands

The world in which we are living is chiral, as well as most of the biologicalmacromolecules constituting of our lives, and these compounds have only oneenantiomeric form in vivo. At the same time, plenty of studies indicated that twoenantiomers of one compound often shown different biological activities, so it isimportant to gain optically pure chiral molecules through some special pathways.This thesis focused on the desired chiral compounds obtained by transitionmetal-catalyzed asymmetric reaction. The ligands containing olefin structure haveshown excellent enantioselectivity and yield in previous articles, so we pay closeattention to the design, synthesis, development and application of chiral alkene andalkene-hybrid ligands.In the thesis, the metal catalyst of transition metal rhodium as well as the chiralalkene and alkene-hybrid ligands were selected to catalyze the asymmetric additionreaction, and obtained good yields and high enantioselectivity in rhodium-catalyzedasymmetric1,4-addition reaction through changing the structure of ligands.In the first, five different chiral diene ligands were synthesized, then the chiralalkene-oxygen ligands were formed by changing the structure of diene toalkene-oxygen, and finally, we synthesized four chiral alkene-phosphine ligands,three N atoms in the aliphatic chain and N atoms in the ring structure afterintroducing the phosphine ligands combined with chiral alkenes.The optimal structure of alkene-hybrid ligands were selected through the yieldand enantioselectivity of the rhodium-catalyze addition reaction of2-cyclohexenoneafter the application chiral alkene and alkene-hybrid ligands.Currently, our study has proved the high yields and enantioselectivity ofalkene-phosphine ligands of which contained N atoms in the cyclic compounds. Theoptimal reaction conditions for the asymmetric1,4-addition reaction of2-cyclohexenone were: chiral ligands and rhodium as catalysts,70℃,4M KOHand1,4-dioxane as solvent.Now alkene-phosphine ligands with proline structure are optimal structure,leading to100%catalytic activity and78%ee value. In the future, our research willmodify better structures of chiral alkene-phosphine ligands with N atoms in thecyclic compounds to obtain the higher enantioselectivity, and this will lay a goodfoundation for the future chiral ligands research.