Ruthenium-catalyzed Diverse Cyclization Of Phthalic Acids And Alkynes

Ruthenium catalyzed C-H bond activation and alkyne cyclization are effective strategies for the construction of diverse and complex polycyclic molecules.Some polycyclic aromatic hydrocarbons(PAHs)have potential applications in materials,medicine and so on.For example,the polysubstituted naphthalene with conjugated ? electron system can be used to prepare organic optoelectronic materials,and some PAHs with isocoumarin skeleton have antibacterial and anticancer activities.In this thesis,we will combine C-H bond activation and diversified alkyne cyclization to establish several efficient and green homogeneous catalytic systems for the construction of a series of diverse and complex polycyclic aromatic hydrocarbons.This thesis consists of three chapters.The first chapter summarizes the previous research results on C–H bond activation,diversified alkyne cyclization,carboxyl directed C–H bond activation,etc.The second chapter is about the methodology of ruthenium catalyzed [2+2+2]cyclization of phthalic acid and alkyne to construct polysubstituted 1-naphthoic acids.We have screened a simple and green reaction condition in which cheap ruthenium is used as catalyst,air as the sole oxidant,?-valerolactone as the green solvent.In addition,the reaction has high atom and step economy.The reaction substrate is compatible with a wide range of electron donating groups such as alkyl and methoxy groups,as well as electron withdrawing group such as halogen and nitro group.The product of polysubstituted 1-naphthoic acids can be derived into a kind of fluorescent group through the Friedel-Crafts reaction.We can also realize double C–H bond activation and multi site functionalization in one pot to further construct oxygen-containing cyclic molecules.Finally,the mechanism was studied in detail and two possible catalytic cycles were proposed.The third chapter is about the ruthenium-catalyzed cyclization of phthalic acid and alkyne to construct a polycyclic molecule with a quaternary carbon center and isocoumarin structure fragment.In this reaction,alkynes act as both C2 synthon and C1 synthon.Choline chloride from biomass was used as an additive,which indicated that the reaction conditionswere simple and green.In addition,the reaction has high atom and step economy.The reaction substrate is compatible with a wide range of electron donating groups,as well as electron withdrawing group.Finally,the reaction mechanism was studied and a possible catalytic cycle was proposed.