Co-catalysis Over Bi-functional Catalysts For Tandem Carbonylations Of Olefins

Tandem carbonylation reaction is defined as a cascade process in which two or more sequential transformation are independently promoted by two or more catalysts to form the value-added chemicals(such as acetals,alcohols,amines)in one pot manner.Co-catalysis,which is in combination with two or more catalytic fiunctions,is the most important strategy to accomplish the one-pot tandem carbonylation.In trandition,co-catalysis involves two kinds of catalysts by physical mixing,which often causes the quenching problems leading to deactivation of the introduced catalysts as well as lacks the intramolecular synergistic effects.The construction of intramolecular bi-functional catalysts not only can solve the quenching problem between the two different catalysts caused by physical mixing,but also can develop the synergistic effect to further improve the tandem transformation.In this thesis,based on the importance of tandem carbonylation and co-catalysis over bi-functional catalysts,a series of intramolecular bi-functional catalysts were developed and studied for the co-catalysis in different tandem carbonylations.The obtained results were summarized as follows:(1)Co-catalysis over "Rh/P complex-P(V)+ Lewis acid" bi-functional catalyst for tandem hydroformylation-acetalizationThe "Rh/P complex-P(V)+ Lewis acid" bi-functional catalysts were constructed on the basis of the bi-functional ligands containing the phosphino-fragments and the Lewis acidic phosphonium(P(V)+).During the reaction process,the incorporated phosphino-fragments could coordinate with Rh-center to serve as "Rh/P complex catalysts" as well as the phosphoniums to serve as Lewis acid organocatalysts.When such bi-functional ligand based Rh-catalyst(Rh/P complex-P(V)+ Lewis acid)were applied to tandem hydroformylation-acetalization(Scheme 1),it was shown that the fist-step hydroformylation was efficiently catalyzed by the Rh/P complex(transition metal catalysis)and the subsequent acetalization was smoothly catalyzed by the Lewis acidic phosphonium fragment(organocatalysis).In addition,the synergetic effect between the Rh/P complex and the Lewis acidic phosphonium were embodied in the tandem reaction,which was not the simple physical mixture of the mono-phosphine and the phosphonium salt.The developed bi-functional ligands based Rh-catalysts exhibited the good generality for this tandem hydroformylation-acetalization with a wide range of olefins in the different alcohols.Under the optimal reaction conditions,the good yields of the acetals in the range of 40-99%were obtained.On the other hand,the selected bi-functional ligand based Rh-catalyst[Scheme 1,Z=(CH2)4]with ionic character could be recycled for 6 times in combination of the room temperature ionic liquid(solvent),without the detectable leaching of Rh and P in the organic products(2)Co-catalysis over ’’Rh/Pcomplex-tautomerf’ bi-functional catalyst for tandem methoxycarbonylation-aminolysisThe“Rh/P complex-tautomer”bi-functional catalyst was constructed on the basis of the bi-functional ligand containing the phosphino-fragment and the tautomer.During the reaction process,the incorporated phosphino-fragment could coordinate with Rh-center to serve as "Rh/P complex catalyst" as well as the tautomer to serve as a"tautomericcatalyst".When such bi-functional ligand based Rh-catalyst(Rh/P complex-tautomer)was applied to tandem methoxycarbonylation-aminolysis(Scheme 2),it was shown that the fist-step methoxycarbonylation was efficiently catalyzed by the Rh/P complex(transition metal catalysis)and the subsequent aminolysis was smoothly catalyzed by the tautomer(organocatalysis).In addition,the synergetic effect between the Rh/P complex and the tautomeric moiety were embodied in the tandem reaction,which was not the simple physical mixture of the mono-phosphine and the tautomeric catalyst.NH3 also served as a ligand to work together with the phosphino-fragment to synergetically modify the performance of Rh-catalyst responsible for the first-step methoxycarbonylation of olefin to generate the esters,and the Rh-tailed tautomeric catalyst was in charge of the subsequent aminolysis to generate the targeted primary amides.The intramolecular concerted effect between Rh-P catalyst and tautomeric catalyst on the formation and stabilization of the critical Rh-complex intermediates were verified by the DFT calculations.The developed bi-functional ligands based Rh-catalysts exhibited the good generality for this tandem methoxycarbonylation-aminolysis with a wide range of olefins.Under the optimal reaction conditions.Under the optimal reaction conditions,the good yields of the amides in the range of 41-100%were obtained.(3)Co-catalysis over,Ru(Ⅲ)/P complex-Ru(Ⅲ)Lewis acid" bi-functional catalyst for tandem hydroformylation-acetalization-hydrogenolysis’Ru(Ⅲ)/P complex-Ru(Ⅲ)Lewis acid" bi-functional catalyst was designed and synthesized,in which the high valence Ru(Ⅲ)-center served as a Lewis acid catalyst as well as coordinated with the phosphine ligand to be a transition metal catalyst(Scheme 3).When this bi-functional catalyst was applied to tandem hydroformylation-acetalization-hydrogenolysis with olefins as the starting materials,it was shown that hydroformylation was eff-iciently catalyzed by the“Ru/P complex"(transition metal catalysis)and the subsequent acetalization was catalyzed by "Ru(Ⅲ)Lewis acid" fragment,while hydrogenolysis was catalyzed by "Ru(Ⅲ)/P complex-Ru(Ⅲ)Lewis acid" bi-functional catalyst(transition metal catalysis).The developed bi-functional catalyst based Ru-catalysts exhibited the good generality for this tandem hydroformylation-acetalization-hydrogenolysis with a wide range of olefins in different alcohols.Under the optimal reaction conditions,the good yields of the alcohols in the range of 60-93%were obtained.