Summaryof main observation and conclusion It could be proposed that gold(I)-catalyzed reactions of ynamides with benzofurazan N-oxidesmightproceed through eitherO-attack or N-attack to affordα-oxo orα-imino Au(I)-ca...Summaryof main observation and conclusion It could be proposed that gold(I)-catalyzed reactions of ynamides with benzofurazan N-oxidesmightproceed through eitherO-attack or N-attack to affordα-oxo orα-imino Au(I)-carbenoidintermediates.Computational studies were performed to predict that benzofurazan N-oxides are ready to undergo the chemoselective N-attack tothe Au(I)-activatedynamides to generate theα-imino Au(I)-carbenoid intermediate.Experimental studies were carried out to confirm the computational results and the 7-nitroindole derivatives were synthesized in a concise and efficient manner.The unfavored O-attack for benzofurazan N-oxides,which is in contrast to nitrones and pyridine/quinoline N-oxides,in the Au(I)-catalyzed reactions with ynamides is rationalized.展开更多
The employment of α-iminometallocarbenes to construct valuable N-containing compounds has attracted significant research interest.Herein,the nucleophilic addition of nitrosoarenes with the α-imino rhodium carbene sp...The employment of α-iminometallocarbenes to construct valuable N-containing compounds has attracted significant research interest.Herein,the nucleophilic addition of nitrosoarenes with the α-imino rhodium carbene species(I),which is derived from Rh_(2)(ll)-catalyzed denitrogenation of 3-diazoindolin-2-imines,to produce synthetically useful 2-iminoindolin-nitrones is described.Mechanistically,the N-attack of nitrosoarenes with the carbene site of I is proposed.For the analogous Rh_(2)(ll)-catalyzed reaction of nitrosoarenes with N-sulfonyl-1,2,3-triazoles reported by Li and co-workers(Org.Lett.2014,16,6394),however,the O-attack of nitrosoarenes with the carbene site of α-imino rhodium carbene species(II)is more favorable to occur than the N-attack.The subsequent transformation to yield the product of N-acylamidines is rationalized based on computational studies.The mechanistic differ-ences for the reactions of nitrosoarenes with a-imino rhodium carbene species I and II are discussed.展开更多
Density functional theory(DFT)calculations were performed to gain an in-depth mechanistic understanding of Ni(0)-and Au(I)-catalyzed diastereoselective[4+2+1]cycloadditions between dienynes and diazo compounds.The com...Density functional theory(DFT)calculations were performed to gain an in-depth mechanistic understanding of Ni(0)-and Au(I)-catalyzed diastereoselective[4+2+1]cycloadditions between dienynes and diazo compounds.The computational results indicate that,for both Ni(0)-and Au(I)-catalysis,transition-metal catalysts are more readily available to activate diazo compounds to form transition-metal carbene intermediates prior to the activation of the dienynes.展开更多
基金We are grateful to the National Natural Science Foundation of China(21973068)the project of scientific and technologic infra-structure of Suzhou(SZS201708)the Priority Academic Pro-gram Development of Jiangsu Higher Education Institutions(PAPD)for financial support.The computational resources utilized in this research were provided by Shanghai Supercomputer Center.
文摘Summaryof main observation and conclusion It could be proposed that gold(I)-catalyzed reactions of ynamides with benzofurazan N-oxidesmightproceed through eitherO-attack or N-attack to affordα-oxo orα-imino Au(I)-carbenoidintermediates.Computational studies were performed to predict that benzofurazan N-oxides are ready to undergo the chemoselective N-attack tothe Au(I)-activatedynamides to generate theα-imino Au(I)-carbenoid intermediate.Experimental studies were carried out to confirm the computational results and the 7-nitroindole derivatives were synthesized in a concise and efficient manner.The unfavored O-attack for benzofurazan N-oxides,which is in contrast to nitrones and pyridine/quinoline N-oxides,in the Au(I)-catalyzed reactions with ynamides is rationalized.
基金the National Natural Science Foundation of China(No.21973068)the Project of Scientific and Technologic Infrastructure of Suzhou(No.SZS201708)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)for financial support.
文摘The employment of α-iminometallocarbenes to construct valuable N-containing compounds has attracted significant research interest.Herein,the nucleophilic addition of nitrosoarenes with the α-imino rhodium carbene species(I),which is derived from Rh_(2)(ll)-catalyzed denitrogenation of 3-diazoindolin-2-imines,to produce synthetically useful 2-iminoindolin-nitrones is described.Mechanistically,the N-attack of nitrosoarenes with the carbene site of I is proposed.For the analogous Rh_(2)(ll)-catalyzed reaction of nitrosoarenes with N-sulfonyl-1,2,3-triazoles reported by Li and co-workers(Org.Lett.2014,16,6394),however,the O-attack of nitrosoarenes with the carbene site of α-imino rhodium carbene species(II)is more favorable to occur than the N-attack.The subsequent transformation to yield the product of N-acylamidines is rationalized based on computational studies.The mechanistic differ-ences for the reactions of nitrosoarenes with a-imino rhodium carbene species I and II are discussed.
基金We are grateful to the National Natural Science Foundation of China(21973068)the project of Scientific and Technologic Infrastructure of Suzhou(SZS201708)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)for financial support.
文摘Density functional theory(DFT)calculations were performed to gain an in-depth mechanistic understanding of Ni(0)-and Au(I)-catalyzed diastereoselective[4+2+1]cycloadditions between dienynes and diazo compounds.The computational results indicate that,for both Ni(0)-and Au(I)-catalysis,transition-metal catalysts are more readily available to activate diazo compounds to form transition-metal carbene intermediates prior to the activation of the dienynes.
