Density functional calculations have been performed to comparatively investigate two possible pathways of Au（I）-catalyzed Conia-ene reaction of β-ketoesters with alkynes. Our studies find that, under the assistance...Density functional calculations have been performed to comparatively investigate two possible pathways of Au（I）-catalyzed Conia-ene reaction of β-ketoesters with alkynes. Our studies find that, under the assistance of trifluoromethanesulfonate （TfO）, the β-ketoester is the most likely to undergo Model II to isomerize into its enol form, in which TfO plays a proton transfer role through a 6-membered ring transition state. The coordination of the Au（I） catalyst to the alkynes triple bond can enhance the eletrophilic capability and reaction activity of the alkynes moiety, which triggers the nucleophilic addition of the enol moiety on the alkynes moiety to give a vinyl-Au intermediate. This cycloisomerizaion step is exothermal by 21.3 kJ/mol with an energy barrier of 56.0 kJ/mol. In the whole catalytic process, the protonation of vinyl-Au is almost spontaneous, and the formation of enol is a rate-limiting step. The generation of enol and the activation of Au（I） catalyst on the alkynes are the key reasons why the Conia-ene reaction can occur in mild condition. These calculations support that Au（I）-catalyzed Conia-ene reactions of β-ketoesters with alkynes go through the pathway 2 proposed by Toste.展开更多
Conia-ene reactions,as a type of ene reactions,have not become a remarkable focus until the beginning of21st century,when Lewis acids served as powerful catalysts and found an increasingly broad utilization in this fi...Conia-ene reactions,as a type of ene reactions,have not become a remarkable focus until the beginning of21st century,when Lewis acids served as powerful catalysts and found an increasingly broad utilization in this field.Consequently,the catalytic Conia-ene reactions have gained great significance in synthetic chemistry due to their high efficiency and atom economy on the construction of valuable cyclic molecules.During the past two decades,the rapid development of transition-metal catalysis and organocatalysis has imposed a profound impact on the exploration of asymmetric Conia-ene reactions.As a result,several strategies have been developed and applied successfully.Organized on the basis of the catalytic system,this review comprehensively presents a summary of recent progress achieved in this emerging domain,aimed at highlighting the reactions’features,practicalities,and the mechanistic rationale is presented where possible.展开更多
文摘Density functional calculations have been performed to comparatively investigate two possible pathways of Au（I）-catalyzed Conia-ene reaction of β-ketoesters with alkynes. Our studies find that, under the assistance of trifluoromethanesulfonate （TfO）, the β-ketoester is the most likely to undergo Model II to isomerize into its enol form, in which TfO plays a proton transfer role through a 6-membered ring transition state. The coordination of the Au（I） catalyst to the alkynes triple bond can enhance the eletrophilic capability and reaction activity of the alkynes moiety, which triggers the nucleophilic addition of the enol moiety on the alkynes moiety to give a vinyl-Au intermediate. This cycloisomerizaion step is exothermal by 21.3 kJ/mol with an energy barrier of 56.0 kJ/mol. In the whole catalytic process, the protonation of vinyl-Au is almost spontaneous, and the formation of enol is a rate-limiting step. The generation of enol and the activation of Au（I） catalyst on the alkynes are the key reasons why the Conia-ene reaction can occur in mild condition. These calculations support that Au（I）-catalyzed Conia-ene reactions of β-ketoesters with alkynes go through the pathway 2 proposed by Toste.
基金financial support from the National Natural Science Foundation of China(Nos.2170217,21772161)the Natural Science Foundation of Fujian Province of China(No.2019J02001)+3 种基金Natural Science Foundation of Shaanxi(No.2018JQ2072)the Youth Training Program of Northwest A&F University(No.2452016006)the President Research Funds from Xiamen University(No.20720180036),PCSIRTScience&Technology Cooperation Program of Xiamen(No.3502Z20183015)。
文摘Conia-ene reactions,as a type of ene reactions,have not become a remarkable focus until the beginning of21st century,when Lewis acids served as powerful catalysts and found an increasingly broad utilization in this field.Consequently,the catalytic Conia-ene reactions have gained great significance in synthetic chemistry due to their high efficiency and atom economy on the construction of valuable cyclic molecules.During the past two decades,the rapid development of transition-metal catalysis and organocatalysis has imposed a profound impact on the exploration of asymmetric Conia-ene reactions.As a result,several strategies have been developed and applied successfully.Organized on the basis of the catalytic system,this review comprehensively presents a summary of recent progress achieved in this emerging domain,aimed at highlighting the reactions’features,practicalities,and the mechanistic rationale is presented where possible.
