Palladium catalyzed Heck-arylation/cyclization cascade: An environmentally benign and efficient synthesis of 4-arylcoumarins in water
作者:Junmin Chen、Wei Liu、Liandi Zhou、Yongli Zhao
DOI:10.1016/j.tetlet.2018.05.032
日期:2018.6
An environmentally benign and efficient approach for the synthesis of 4-arylcoumarins from ortho-hydroxy cinnamate ester derivatives with aryl iodides was developed in water under aerobic conditions. This transformation proceeds through a palladiumcatalyzed Heck-arylation/cyclization cascade reaction. The present protocol features a wide substrate scope and readily available starting materials to
coumarin-3-carboxylic acids is developed. This approach enables controlled protodecarboxylation/regioselective C–H arylation of coumain-3-carboxylic acids in one-pot using a monometallic catalytic system. A wide variety of electron-donating and -withdrawing substituents on both coumarins and arylboronic acid are tolerated under the reaction conditions and 4-aryl coumarins are constructed in high yields.
An efficient protocol for the direct synthesis of 4-arylcoumarins via palladium-catalyzedoxidativeHeck coupling reaction of coumarins and arylboronicacids was developed. 4-Arylcoumarins were obtained in moderate to excellent yields, and the reaction also showed tolerance toward functional groups such as hydro, methoxy, diethylamino, nitro, and chloro groups.
Room Temperature Nickel(0)-Catalyzed Suzuki-Miyaura Cross-Couplings of Activated Alkenyl Tosylates: Efficient Synthesis of 4-Substituted Coumarins and 4-Substituted 2(<i>5H</i>)- Furanones
作者:Zhen-Yu Tang、Qiao-Sheng Hu
DOI:10.1002/adsc.200404150
日期:2004.12
Roomtemperaturenickel(0)/tricyclohexylphosphine [Ni(0)/PCy3]-catalyzed Suzuki–Miyaura cross-couplings of 4-(p-toluenesulfonyloxy)coumarins and 4-(p-toluenesulfonyloxy)-2(5H)-furanone with arylboronicacids are described in this communcation. Our study shows that activated alkenyl tosylates possess higher activities than aryl tosylates in the Suzuki–Miyaura cross-couplings. The mild reaction conditions
Photoinduced cyclization of alkynoates to coumarins with N-Iodosuccinimide as a free-radical initiator under ambient and metal-free conditions
作者:Zhihui Wang、Xuezhi Li、Lei Wang、Pinhua Li
DOI:10.1016/j.tet.2019.01.013
日期:2019.2
a free-radical initiator and under LED (380–385 nm) irradiation and metal-free conditions, the reaction of alkynoates underwent smoothly to afford the corresponding coumarins in high yields at room temperature with broad substrate scope via freeradical intramolecular cyclization and ester rearrangement.