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
Copper/Selectfluor-System-Catalyzed Dehydration-Oxidation of Tertiary Cycloalcohols: Access to β-Substituted Cyclohex-2-enones, 4-Arylcoumarins, and Biaryls
作者:Shaobo Ren、Jian Zhang、Jiahui Zhang、Heng Wang、Wei Zhang、Yunkui Liu、Miaochang Liu
DOI:10.1002/ejoc.201500610
日期:2015.8
A route to β-substitutedcyclohex-2-enones, 4-arylcoumarins, and biaryls has been developed. This approach involves a one-pot Cu0/Selectfluor-catalyzed dehydration–oxidation of tertiary cycloalcohols. Thus, by using 2 equiv. of Selectfluor at 25 °C, the dehydration–oxidation of tertiary cyclohexanols and oxabenzocyclohexanols gave β-substitutedcyclohex-2-enones and 4-arylcoumarins, respectively; whereas
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.
Cascade Synthesis of 4-Arylcoumarins: Pd-Catalyzed Arylations and Cyclizations with (<i>E</i>
)-Ethyl 3-(2-Hydroxyaryl)acrylates and Triarylantimony Difluorides
The reactions of 3‐(2‐hydroxyaryl)acrylates with triarylantimony difluorides in the presence of Pd(OAc)2 and 2,2'‐bipyridyl under aerobic conditions afforded 4‐arylcoumarins in good‐to‐excellent yields with all of the arylgroups in the triarylantimony difluoride transferred to the coupling products. This protocol increases the synthetic scope of 4‐arylcoumarins, especially those bearing electron‐withdrawing