Recently,homogeneous gold catalysis has attracted tremendous attention and has also been widely used in multistep synthesis.The current reaction methodology starts from the gold activation of unsaturated carbon bond a...Recently,homogeneous gold catalysis has attracted tremendous attention and has also been widely used in multistep synthesis.The current reaction methodology starts from the gold activation of unsaturated carbon bond and subsequent nucleophilic attack.The combination of a gold catalyst with another acid catalyst,including Brønsted acid and Lewis acid,is possible to bring two distinctive catalytic systems together and deliver unprecedented new reactions.More essentially,it avoids the purification of unstable intermediates and improves the step and atom economy.Here,the recent progress in the Au/Acid combined catalysis is reviewed,including the scope of reactions,mechanism and synthetic applications.展开更多
Chromenes represent an important class of six-membered heterocycles and have drawn tremendous attention in recent years. In this article, we report a convenient and practical synthesis of this heterocycle by a silver(...Chromenes represent an important class of six-membered heterocycles and have drawn tremendous attention in recent years. In this article, we report a convenient and practical synthesis of this heterocycle by a silver(I)-catalyzed cycloaddition reaction between in situ generated ortho-quinone methides and N-allenamides. Diverse 4H-chromenes were synthesized in good to excellent yields under very mild conditions.展开更多
The construction of all-carbon molecule frameworks remains challenging. Herein, we report a facile and efficient one-pot synthesis of a novel all-carbon stair containing dimerized pentalene core using inexpensive cycl...The construction of all-carbon molecule frameworks remains challenging. Herein, we report a facile and efficient one-pot synthesis of a novel all-carbon stair containing dimerized pentalene core using inexpensive cyclopropyl alkyne catalyzed by in situ generated Cu(I) from the comproportionation reaction of Cu(II) salt and Cu powder under mild reaction conditions. The reaction proceeds via sequential acetylenic coupling, followed by cyclization and [2 + 2] cycloaddition to directly produce pentalene dimer, which is difficult to access by other established methods. Different mechanistic paths were studied for the pentalene formation using density functional theory, suggesting that the reaction also proceeds through acetylenic coupling followed by cyclization and [2 + 2] cycloaddition. Based on the activation energy barriers, Path 1 has the rate-determining step of 38.63 kcal/mol, which is the most thermodynamically preferred one among the four paths.展开更多
基金Natural Science Foundation of China(No.21102085)the Fundamental Research Funds of Shandong University(No.2014JC008)the Subject Construction Funds of Shandong University(No.104.205.2.5).
文摘Recently,homogeneous gold catalysis has attracted tremendous attention and has also been widely used in multistep synthesis.The current reaction methodology starts from the gold activation of unsaturated carbon bond and subsequent nucleophilic attack.The combination of a gold catalyst with another acid catalyst,including Brønsted acid and Lewis acid,is possible to bring two distinctive catalytic systems together and deliver unprecedented new reactions.More essentially,it avoids the purification of unstable intermediates and improves the step and atom economy.Here,the recent progress in the Au/Acid combined catalysis is reviewed,including the scope of reactions,mechanism and synthetic applications.
基金supported by the National Natural Science Foundation of China(21572118,21750110444)the Natural Science Foundation of Shandong Province(ZR2018MB010)+1 种基金subject construction funds(104.205.2.5)Tang scholar award of Shandong University
文摘Chromenes represent an important class of six-membered heterocycles and have drawn tremendous attention in recent years. In this article, we report a convenient and practical synthesis of this heterocycle by a silver(I)-catalyzed cycloaddition reaction between in situ generated ortho-quinone methides and N-allenamides. Diverse 4H-chromenes were synthesized in good to excellent yields under very mild conditions.
基金financially supported by the National Natural Science Foundation of China (Nos. 91961105, 21822107,21571115, 21827801)the Natural Science Foundation of Shandong Province (Nos. ZR2019ZD45, JQ201803 and ZR2017MB061)+2 种基金the Taishan Scholar Project of Shandong Province of China (Nos.tsqn201812003 and ts20190908)Project for Scientific Research Innovation Team of Young Scholar in Colleges and Universities of Shandong Province (No. 2019KJC028)Natural Science Foundation of Shandong Province (No. ZR2020ZD35)。
文摘The construction of all-carbon molecule frameworks remains challenging. Herein, we report a facile and efficient one-pot synthesis of a novel all-carbon stair containing dimerized pentalene core using inexpensive cyclopropyl alkyne catalyzed by in situ generated Cu(I) from the comproportionation reaction of Cu(II) salt and Cu powder under mild reaction conditions. The reaction proceeds via sequential acetylenic coupling, followed by cyclization and [2 + 2] cycloaddition to directly produce pentalene dimer, which is difficult to access by other established methods. Different mechanistic paths were studied for the pentalene formation using density functional theory, suggesting that the reaction also proceeds through acetylenic coupling followed by cyclization and [2 + 2] cycloaddition. Based on the activation energy barriers, Path 1 has the rate-determining step of 38.63 kcal/mol, which is the most thermodynamically preferred one among the four paths.
