Synthesis Of Chiral Acylsilanes By Asymmetric Copper-catalyzed Conjugate Addition Of Diethylzinc To α,β-unsaturated Acylsilanes

In recent years,the synthesis and application of organosilicon compounds has attracted more and more attention,and has been widely used in medicine,photoelectric materials,etc.However,its synthesis method is still relatively limited,especially the synthesis of chiral organosilicon compounds and their application is still a challenging topic.In this dissertation,the catalytic asymmetric reactions involving chiral organosilicon compounds are mainly focused on the chiral ligand-controlled metal-catalyzed synthesis of novel organosilicon compounds,and the preliminary exploration on the construction of silicon-stereogenic centers and the related asymmetric transformation.In the first part of the research work,we first developed an asymmetric 1,4-conjugate addition reaction of copper-catalyzed diethylzinc with α,β-unsaturated acylsilanes,based on the performance testing of a large number of chiral ligands.It was found that under the control of HZNU-Phos,the ee value of the conjugate addition products can reach up to 85%,which is the best enantioselectivity achieved in this type of reaction.In the second part of the work,Considering the Si-containing four-membered ring compounds have a variety of possible reaction pathways,we use the selective ring expansion reaction of the benzene-silicon four-membered ring and dimethyl acetylenedicarboxylate as a model reaction and investigate the stereoselective induction of the chiral ligands to regulate the reaction conditions so that the same silicon four-membered ring substrate can obtain different products under different catalytic conditions.The experimental data shows that the reaction can make the racemic silicon-containing four-membered compounds to the synthesis of the chiral product with a moderate ee value by the ring expansion reaction of the four-membered ring compound.In summary,based on the detailed investigation on the synthesis of dozens of chiral ligands,we have systematically studied the asymmetric copper-catalyzed conjugate addition of diethylzinc to α,β-unsaturated acylsilanes through extensive screening.In this reaction,good yields and stereoselectivities could be achieved under the optimized reaction conditions.The exploratory study on the stereoselective ring expansion of silicon-containing four-membered ring with dimethyl acetylenedicarboxylate has been carried out,and preliminary research results have been obtained in this work,providing valuable research experience for the subsequent development of novel chiral phosphine ligands.