A new route to substituted furocoumarins <i>via</i> copper-catalyzed cyclization between 4-hydroxycoumarins and ketoximes
作者:Tuong A. To、Yen H. Vo、Anh T. Nguyen、Anh N. Q. Phan、Thanh Truong、Nam T. S. Phan
DOI:10.1039/c8ob01064a
日期:——
A newroute to substituted furocoumarins via copper-catalyzed cyclization between 4-hydroxycoumarins and ketoximes was developed. CuBr2 exhibited higher activity than other copper salts, affording the desired furocoumarins in high yields. The transformation proceeded readily in the absence of stoichiometric external oxidants. The significance of this synthetic strategy would be (1) the easily available
Copper-catalyzed radical/radical cross-coupling of ketoxime carboxylates with 4-hydroxycoumarins: A novel synthesis of furo[3,2-c]-coumarins
作者:Mingchuang He、Zhaohua Yan、Wangyang Wang、Fuyuan Zhu、Sen Lin
DOI:10.1016/j.tetlet.2018.09.007
日期:2018.10
A novel and efficient strategy for the synthesis of furo[3,2-c]coumarins has been developed via copper-catalyzed radical/radical cross-coupling of ketoxime carboxylates with 4-hydroxycoumarins. This redox-neutral reaction allows smooth and selective synthesis of 2-substituted, 3-substituted, 2,3-disubstituted and 2,3-fused polycyclic furo[3,2-c]coumarins.
通过铜催化酮肟肟酸酯与4-羟基香豆素的自由基/自由基交叉偶联,已经开发了一种新型有效的合成呋喃[3,2- c ]香豆素的策略。该氧化还原中性反应允许2-取代,3-取代,2,3-二取代和2,3-稠合的多环呋喃[3,2- c ]香豆素的平滑和选择性合成。
Elemental tellurium mediated synthesis of 2-(trifluoromethyl)oxazoles using trifluoroacetic anhydride as reagent
作者:Beibei Luo、Zhiqiang Weng
DOI:10.1039/c8cc05670f
日期:——
An elemental tellurium mediated synthesis of 2-(trifluoromethyl)oxazoles from the reaction of acetophenone oxime acetates with trifluoroacetic anhydride has been developed. This new tandem cyclization proceeds in good to excellent yields via a SET reduction followed by a 5-endo-trig pathway. Some of the title compounds showed fungicidal and insecticidal activities.
An efficient synthesis of polysubstituted pyrroles via copper-catalyzed coupling of oxime acetates with dialkyl acetylenedicarboxylates under aerobic conditions
A Cu-catalyzed [3+2]-type condensation reaction of oxime acetates and dialkyl acetylenedicarboxylates that provides highly substituted pyrroles under aerobic conditions is described. The newly formed pyrroles are easily employed for further transformations to prepare pyrrolo[2,1-a]isoquinoline skeletons.
A novel ruthenium-catalyzed cyclization of ketoxime carboxylates with N,N-dimethylformamide (DMF) for the synthesis of tetrasubstituted symmetrical pyridines has been developed. A methyl carbon on DMF performed as a source of a one carbon synthon. And NaHSO3 plays a role in the reaction.