A method of C（sp^3）-H bond functionalization of methyl azaarenes catalyzed by alumina-supported heteropoly acid and addition to isatins was developed. This transformation could be used for the synthesis of biologica...A method of C（sp^3）-H bond functionalization of methyl azaarenes catalyzed by alumina-supported heteropoly acid and addition to isatins was developed. This transformation could be used for the synthesis of biologically important 3-hydroxy-2-oxindole derivatives in good to excellent yields and the catalyst could be reused for six times without significant decrease in activity.展开更多
通过亚胺自由基引发的1,5-氢原子转移(Hydrogen Atom Transfer,HAT)途径实现C(sp^(3))—H键官能团化,可避免导向基团和当量氧化剂的使用,因而引起了研究人员的广泛关注。近年来,过渡金属和可见光氧化还原体系的发展为高效可控产生亚胺...通过亚胺自由基引发的1,5-氢原子转移(Hydrogen Atom Transfer,HAT)途径实现C(sp^(3))—H键官能团化,可避免导向基团和当量氧化剂的使用,因而引起了研究人员的广泛关注。近年来,过渡金属和可见光氧化还原体系的发展为高效可控产生亚胺自由基提供了可靠的方法。本文根据亚胺自由基的来源分类总结了亚胺自由基引发的1,5-氢原子转移实现C(sp^(3))—H键官能团化反应。展开更多
A theoretical study is carried out on Gaunt＇s palladium-catalyzed selective C（sp3）-H activation of unprotected aliphatic amines. In this reaction, the methyl group is proposed to be activated through a four-membere...A theoretical study is carried out on Gaunt＇s palladium-catalyzed selective C（sp3）-H activation of unprotected aliphatic amines. In this reaction, the methyl group is proposed to be activated through a four-membered cyclometallation pathway even though an ethyl group is present in the substrate. Our calculation shows that the methyl and ethyl activation processes proceed in nitrogen-atom-directed pathway rather than carbonyl-directed one. More important, methyl activation is more favorable than ethyl activation with nitrogen atom as the directing group. Further studies on the structural parameters show that the lactone structure in cyclic substrate is the origin of the selective methyl activation. When the lactone moiety is changed to ketone, ether or alkyl, the selectivity could be reversed so that the ethyl activation becomes more favorable. This result validates the pro- oosal that lactone structure is key to selective methyl activation.展开更多
基金Financial support from the National Natural Science Foundation of China(No.21402103)the research fund of Qingdao Agricultural University's High-level Person(No.631303)the Scientific Research Foundation of Shandong Province Outstanding Young Scientist Award(No.BS2013YY024) were gratefully acknowledged
文摘A method of C（sp^3）-H bond functionalization of methyl azaarenes catalyzed by alumina-supported heteropoly acid and addition to isatins was developed. This transformation could be used for the synthesis of biologically important 3-hydroxy-2-oxindole derivatives in good to excellent yields and the catalyst could be reused for six times without significant decrease in activity.
文摘通过亚胺自由基引发的1,5-氢原子转移(Hydrogen Atom Transfer,HAT)途径实现C(sp^(3))—H键官能团化,可避免导向基团和当量氧化剂的使用,因而引起了研究人员的广泛关注。近年来,过渡金属和可见光氧化还原体系的发展为高效可控产生亚胺自由基提供了可靠的方法。本文根据亚胺自由基的来源分类总结了亚胺自由基引发的1,5-氢原子转移实现C(sp^(3))—H键官能团化反应。
基金supported by the National Natural Science Foundation of China(21325208,21172209,21361140372,21202006)the National Basic Research Program of China(2012CB215306)+2 种基金Financial Resources Federal Credit Union(WK2060190025,WK2060190040,FRF-TP-14-015A2)Chinese Academy of Sciences(KJCX2-EW-J02)Program for Changjiang Scholars and Innovative Research Team and the supercomputer center of Shanghai and USTC
文摘A theoretical study is carried out on Gaunt＇s palladium-catalyzed selective C（sp3）-H activation of unprotected aliphatic amines. In this reaction, the methyl group is proposed to be activated through a four-membered cyclometallation pathway even though an ethyl group is present in the substrate. Our calculation shows that the methyl and ethyl activation processes proceed in nitrogen-atom-directed pathway rather than carbonyl-directed one. More important, methyl activation is more favorable than ethyl activation with nitrogen atom as the directing group. Further studies on the structural parameters show that the lactone structure in cyclic substrate is the origin of the selective methyl activation. When the lactone moiety is changed to ketone, ether or alkyl, the selectivity could be reversed so that the ethyl activation becomes more favorable. This result validates the pro- oosal that lactone structure is key to selective methyl activation.
