Diacylation of coumarins by silver-catalyzed decarboxylative cross-coupling
作者:Hua Wang、Shi-Liu Zhou、Li-Na Guo、Xin-Hua Duan
DOI:10.1016/j.tet.2014.12.029
日期:2015.1
A mild silver-catalyzeddecarboxylative acylation of coumarins has been developed by using α-oxocarboxylicacids as acyl sources. This protocol provides an efficient and straightforward access to aroyl substituted coumarins in moderate to excellent yields with good selectivities. Furthermore, the reaction conditions were also applicable to quinolinones and naphthoquinones, affording the corresponding
Copper-Catalyzed Regioselective Cross-Dehydrogenative Coupling of Coumarins with Benzylic C<sub>sp3</sub>-H Bonds
作者:Shi-Liu Zhou、Li-Na Guo、Xin-Hua Duan
DOI:10.1002/ejoc.201403068
日期:2014.12
A new copper-catalyzed regioselective cross-dehydrogenativecoupling of coumarins with benzylic Csp3–H bonds has been developed. This reaction provides direct access to a wide range of 3-benzylcoumarins in moderate to good yields. The protocol was also extended successfully to other heterocyclic compounds, such as quinolinones.
Mn(OAc)3-mediated direct Csp2-H radical trifluoromethylation of coumarins with CF3SO2Na (Langlois reagent) to afford selective 3-trifluoromethyl coumarins in moderate to good yields is described. This methodology can also be applied to the trifluoromethylation of quinolinones and pyrimidinones.
Peroxodisulfate-assisted three-component benzylation of coumarins with styrenes and KSCN: a transition-metal-free approach for the synthesis of 3-(1-aryl-2-thiocyanatoethyl)-2<i>H</i>-chromen-2-one in ethyl lactate
作者:Palani Natarajan、Priya、Deachen Chuskit
DOI:10.1039/d1gc01382c
日期:——
Peroxodisulfate-assisted three-component benzylation of coumarins with styrenes and KSCN to 3-(1-aryl-2-thiocyanatoethyl)-2H-chromen-2-one is reported for the first time. This reaction proceeds via the consecutive addition of the SCN radical to styrenes followed by the addition of the resultant substituted-benzylic radical to the C3-position of coumarin derivatives. In contrast to previous approaches
首次报道了过二硫酸盐辅助香豆素与苯乙烯和 KSCN 的三组分苄基化反应生成 3-(1-aryl-2-thiocyanatoethyl)-2 H -chromen-2-one。该反应通过将 SCN 基团连续加成到苯乙烯上,然后将得到的取代苄基基团加成到香豆素衍生物的 C 3位进行。与以前通常需要过渡金属催化、有毒的挥发性有机溶剂、碱和高温的方法相比,香豆素的苄基化策略是无过渡金属和无碱的,并且在环境条件下适用于乳酸乙酯作为一种绿色介质。
Copper(I)-Catalyzed 3-Position Methylation of Coumarins by Using Di-<i>tert</i>-butyl Peroxide as the Methylation Reagents
作者:Huan Zhuang、Runsheng Zeng、Jianping Zou
DOI:10.1002/cjoc.201500836
日期:2016.4
The copper‐catalyzed methylation of coumarin by using di‐tert‐butyl peroxide (DTBP) has been described. The reaction provides direct access to a wide range of 3‐methylcoumarins in moderate to good yields. In this procedure, it is noteworthy that DTBP was employed not only as the oxidant, but also as the methyl source.