Studies Of Palladium Catalyzed Aerobic Oxidative Heck Reactions Of Indolizines And Their Mechanism

Indolizine is a kind of important heterocyclic substrate,which is widely used in the field of biology,medicine and material sciences.The activation of C-H bond of indolizine has been attracting an increased interest of synthetic chemists.This thesis concentrates on the oxidative Heck reaction of indolizine at 1-position and 3-position.The study of reaction mechanism research also is included.The main contents of the work are listed as below.1.A new synthetic method via palladium catalyzed aerobic oxidative Heck Reaction of indolizines at 1-position was developed.After screening the reaction conditions,the best reaction conditions were confirmed:using palladium acetate as the catalyst,O2 as the oxidant,potassium acetate and copper acetate as the additive,DMA:DMSO=9:1 as the solvent and heating under 110℃.This paper also explored the scope of the substrates with a variety of indolizines and olefins.An array of 1-substituted indolizines were obtained with moderate to good yield.The mechanism studies revealed that the reaction started with the C-H activation of indolizine and through a Pd(Ⅱ)/Pd(0)catalytic cycles.Kinetic studies confirm that the cleavage of the C-H bond in indolizine was the rate determining step.2.A new synthetic method via palladium catalyzed aerobic oxidative Heck Reaction of indolizines at 3-position was developed.After screening the reaction conditions,the best reaction conditions were confirmed:using palladium acetate as the catalyst,O2 as the oxidant,potassium acetate as the additive,DMSO as the solvent and heating under 100℃.The substrate scope of indolizines and olefins were also examined under optimal reaction conditions.