Synthesis Of Silicon-tethered Thienocyclopentadienylzirconium(Ⅳ)

Metallocene catalysts have attracted extensive attention in the industrial field due to their high activity for olefin polymerization.Among them,metallocene compound with tethered structures and specific symmetries,exhibiting significant for catalyzing the stereocontrollable polymerization of propylene,have great potential of industrialization and commercialization.At present,most metallocene catalysts have low synthesis efficiency,unstable quality and high production cost,which seriously restrict their industrial production.In this thesis,the development of a concise and efficient synthetic route was described for the synthesis of 6,6’-dimethylsilylbis（2,5-dimethyl-3-phenyl-cyclopento[2,3-b]thiophen-6-yl）zirconium dichloride,a C₂symmetric zirconocene complex with dimethylsilicon tether and thieno rings.This work paved the way for the synthesis of other structurally similar metallocene complex,as well as the designs,syntheses and screenings of novel highly active and stereoselective metallocene catalysts based on these templates.In this thesis we summarized and analyzed the synthesis research on 6,6’-dimethylsilylbis（2,5-dimethyl-3-phenyl-cyclopento[2,3-b]thiophen-6-yl）zirconium dichloride in the existing literature at first,we designed our synthetic strategies specifically to solve the problems of high contamination of reagents,high risks and poor reaction regioselectivity in existing synthetic routes.We propose a new method based on Friedel-Crafts acylation tandem Nazarov cyclization to complete the[5-5]ring skeleton construction of the thienolocene structure in the ligand,and then introduce the phenyl group through Suzuki coupling to complete the structural modification.After this,the cyclopentadiene ring is constructed by adjusting the oxidation state then introducing the silicon tether and finally coordinated with bis（tetrahydrofuran）zirconium tetrachloride.At present,the industrial synthesis of metallocene catalysts is still the traditional batch tank process.In order to solve the problems of uneven heat and mass transfer,poor reaction reproducibility and serious production energy consumption,we hope to combine the synthesis of metallocene catalysts with continuous flow technology,to realize the green and efficient synthesis of metallocene catalysts by utilizing its efficient heat and mass transfer efficiency and good reaction parallelism.To this end,we firstly optimized the conditions of batch synthesis,and paid attention to the design of reagents and reactant states at the same time.We developed conditions more suitable for continuous flow technology,such as solid-catalyzed Nazarov cyclization and carbonyl reduction based on homogeneous reducing agent borane-tetrahydrofuran to prepared for the subsequent synthesis based on continuous flow technology.On this basis,we made a preliminary study on the application of continuous flow technology in synthesis,which significantly improved the reaction efficiency of Nazarov cyclization and hydroxyl elimination reactions,laid the foundation for the full-route flow synthesis of 6,6’-dimethylsilylbis（2,5-dimethyl-3-phenyl-cyclopento[2,3-b]thiophen-6-yl）zirconium dichloride.