Synthesis Of Ruthenium Complexes With 8-phosphinoquinoline Ligands And Their Reactivity With Terminal Alkynes

Ruthenium vinylidene complexes has attracted long-term attention due to their rich reactivity as well as their facile formation from the reactions of transition metal complexes with terminal alkynes,which have rendered them important application in the catalytic reaction involving terminal alkynes.In this thesis,we have carried out investigations focused on the reactivity of 8-phosphinoquinoline ruthenium vinylidene complexes.A series of new 8-phosphinoquinoline ruthenium complexes were synthesized.Their catalytic properties for the cycloisomerization of alkynols and their reactions with terminal alkynes were studied.This dissertation is divided into the following four chapters:Chapter 1 is the introduction,which mainly summarizes the preparation methods,and the reaction properties of ruthenium vinylidene complexes as well as their applications in organic synthesis.The research progress of catalytic endo-cycloisomerization of terminal alkynols via vinylidene intermediates was also introduced.The common synthetic methods of 8-phosphinoquinoline ligands and their applications in organometallic chemistry were briefly described as well.Finally,the research ideas and purposes of this paper are presented.In chapter 2,in view of the current situation on the lack of catalytic systems for the 7-and 8-endo cycloisomerization of terminal alkynols,we studied the catalytic activity of 8-(diphenylphosphino)quinidine ruthenium complexes with acetate ligand for endo-cycloisomerization of aliphatic terminal alkynols based on the previous work of our group.The reaction of the chloride ruthenium oxacyclohepta carbene complex[RuCl{=C(CH2)5O}(DPPQ)2][BPh4](2-2')with silver acetate was investigated,which produced the corresponding cyclic enol ether product smoothly.This result indicate that introducing of acetate ligand into the complex could facilitate the deprotonaton of the oxacyclocabene that leads to release the cyclic enol ether by subsequent protonation,and thus confirmed that the intramolecular acetate-assisted deprotonation-protonation strategy can effectively promote the conversion of carbene 2-2' to the corresponding cyclic enlo ethers product.Based on this result,a series of acetate-coordinated ruthenium complexes were synthesized and characterized,including cis-[Ru(DPPQ)2(k2-OAc)][X](2-3a,X=BPh4;2-3aF,X=BArF4)and trans-[Ru(DPPQ)2(k2-OAc)][X](2-3b,X=BPh4;2-3bF,X=BArF4),and were tested as catalyst for the cycloisomerization of aliphatic terminal acetylenic alkynols.By using 2-3bF as the catalyst,the 7-and a-endo cycloisomerization can be achieved and a series of cyclization product can be obtained in moderate to good yield.Moreover,the catalyst is also suitable for the 7-endo cycloisomerization of aromatic terminal alkynols.In chapter 3,new ruthenium complexes with the 8-diisopropylphosphinoquinoline ligand were synthesized and their reaction properties with terminal alkynes were studied to investigate the influences of the substituents of the phosphine of 8-phosphinoquinoline ligands and the substituents of the alkynes on the formation and the stability of the vinylidene complexes.A series of ruthenium complexes such as Ru(D1PrPQ)2Cl2(3-2),[Ru(?-Cl)(DiPrPQ)2]2[BPh4]2(3-3),[Ru(DiPrPQ)2PyCl][BPh4](3-4),[Ru(DiPrPQ)2(MeCN)Cl][BPh4](3-5)and[Ru(DiPrPQ)2(k2-OAC)][BPh4](3-6)were synthesized and characterized and a series of corresponding ruthenium vinylidene complexes containing different substituents including[RuCl(=C=CHR)(DiPrPQ)2][BPh4](3-7a,R=p-C6H4OMe;3-7b,R=Ph;3-7c,R=p-C6H4F;3-7d,R=tBu)can be obtained in high yield by treatment of 3-3 with the reapective terminal alkynes.The effect of substituents with different electronic properties on the terminal alkynes for the formation and dissociation of ruthenium vinylidene complexes was investigated.In addition,the ruthenium allenylidene complex[RuCl(=C=C=CPh2)(DiPrPQ)2][BPh4](3-10)was obtained from the reaction of 3-3 with the terminal propargyl alcohol,from which the y-hydroxy ruthenium vinylidene intermediate[RuCl{=C=CH-C(OH)Ph2}(DiPrPQ)2][BPh4](3-9)can be observed.The reaction properties of the DiPrPQ complex 3-3 and the DPPQ one 2-1 toward terminal alkynes were also compared.In chapter 4,the research of this thsis was summarized.