Synthesis Of Novel Phosphine Ligands For Catalytic Construction Of Silicon-Stereogenic Centers

In recent years,with the rapid development of asymmetric catalysis,there had been more advanced methods of synthesis of chiral silane based on asymmetric catalysis.For example,there are transition-metal or enzyme-catalyzed functionalization of prochiral organosilane besides traditional methods included substrates-induced protocol.Silicon-stereogenic chiral organosilanes are a family of unique species and possess attractive reactivities.Fellow this thesis,we focus on synthesis of novel phosphine ligands for catalytic construction of silicon-stereogenic centers.Firstly,tetraaryl-1,3-dioxolane-4,5-dimethanols(TADDOL)were obtained from the reaction of the chiral tartrate with the Grignard reagent,TADDOL-derived phosphoramidites are commonly prepared by the reaction of the TADDOL with phosphorus trichloride in the presence of a base such as triethylamine to give chlorophosphite,followed by reaction of chlorophosphite with the appropriate amine.These phosphoramidite ligands inherited the feature of TADDOL-based backbone and contain the features which were important for this reaction in the stereoselective induction of silicon-carbon bond-forming silylation.Recently,we developed a novel phosphine ligand and examined it's activity in intramolecular desymmetrizing hydrosilylation.The screening and optimization of reaction conditions,especially with the development of new P-ligand by modification of Ar-BINMOLs-derived phosphoramidite ligands,resulted in the determination of an efficient procedure,which provided the corresponding silicon-stereogenic silanes in moderate yields and good enantioselectivities under mild reaction conditions.In addition,to the best of our knowledge,it is one of the best examples of intramolecular desymmetrizing hydrosilylation reaction for a stereoselective synthesis of silicon-stereogenic silanes with good enantioselectivity.Preliminary studies have shown that our novel phosphine ligands play a critical role in intramolecular hydrosilylation.