Design And Synthesis Of Diene Ligand And Palladium-catalysed Cyclisations Of Enynesy

Organometallic Chemistry is one of the cornerstones of modern synthetic chemistry.The transition metal-catalyzed reactions are mild,simple,highly,selective and efficiently,which provides a concise and efficient method to construct C-C bonds.Chirality is widely found in natural products and biologically active molecules.Therefore,the transition metal-catalyzed cascade reaction to construct multi-bonds in one-step sequentially has become a frontier in organic synthesis.This thesis mainly focuses on the rhodium-catalyzed asymmetric arylation of nitroolefins(RCAA)and palladium-catalysed cyclisations of 1,7-enynes.Furthermore,asymmetric counteranion-directed catalysis(ACDC)cyclisations of enynes has been developed,which affords an indene derivatives with an all-carbon quaternary stereogenic centers.This thesis could be divided into the following three parts:In the first part,a phellandrene-derived,norde-hydroabietyl amide-containing chiral diene ligand was designed and synthesized.It was applied to the rhodium catalyzed-asymmetric arylation of nitroolefins.The optimization conditions screened by investigating the effect of solvents,bases and other liands on product yield and ee.On this point of view,the chiral diene ligand was employed to RCAA of various nitroalkenes and aryl boronic acids.Furthermore,we also realized asymmetric1,6-RCAA to cyclic dienones by comparing NDAA-chiral diene with chiral diene counterparts.We have achieved a high enantioselectivity at scale-up levels of RCAA.Kinetic experiments were conducted to investigate the chirality-inducing match between two fragments of norde-hydroabietyl amide and phellandrene.Studies have shown that the phellandrene moiety plays a decisive role in surface selectivity of the substrate in the chiral induction of RCAA.There is no significant match-mismatchbetween two chiral fragments of norde-hydroabietyl amide and diene,but the steric hindrance effect of the norde-hydroabietyl fraction promoted the increase of ee in RCAA.In the second part,we studied the dehydroabietic acid(DAA)catalysed or promoted palladium-catalysed cyclisations of arene-tethered 1,7-enynols to form benzocyclic dienols.Solvent effect,temperatures and Br?nsted acids were studied.Furthermore,6,6,6,5-tetracyclic lactones are accessible by one-pot Diels-Alder reaction / lactonisation from dienols.On the other hand,we studied the palladium-catalysed cylisations of 1,7-enynoates and reported the first cases of ACDC concept in palladium-catalyded cyloiomerisation of enynes with quaternary stereogenic carbon embeded indene building blocks.