Copper-Mediated Homocoupling of Vinyl Dibromides to Symmetrical Diynes
摘要:
1,1-Dibromoalk-1-enes were dimerized readily in the presence of copper iodide, a diamine ligand, and cesium carbonate in DMF to give symmetrical 1,3-diynes. The reaction was found to be selective and rather general, furnishing the corresponding diynes in good yields, even with complex and sensitive dibromides, and provides useful insights into the reactivity of 1,1-dibromoalk-1-enes with copper(I).
An efficient and stereoselective procedure for the preparation of E-1-alkenylphosphonates by copper-mediated cross-coupling between 1,1-dibromo-1-alkenes and dialkyl phosphites is reported. The reaction allows for formal substitution of both bromine atoms, respectively, by an hydrogen and a dialkoxyphosphoryl.
Copper-Mediated Selective Cross-Coupling of 1,1-Dibromo-1-alkenes and Heteronucleophiles: Development of General Routes to Heterosubstituted Alkynes and Alkenes
site-selective, double, or alkynylative cross-coupling, therefore providing divergent and straightforward entries to numerous building blocks such as bromoenamides, ynamides, ketene N,N-acetals, bromoenol ethers, ynol ethers, keteneO,O-acetals, or vinylphosphonates and further expanding the copper catalysis toolbox with useful and versatile processes.
Palladium/copper-catalyzed tandem Sonogashira coupling/lactonization of methyl 2-(2′,2′-dibromovinyl)benzoate with terminal alkynes: Facile access to 3-alkynyl isocoumarins
作者:Xiaozu Liu、Guojun Chen、Yuxiang Zhou、Peijun Liu
DOI:10.1016/j.tetlet.2018.07.017
日期:2018.8
An efficient palladium/copper-catalyzed tandem Sonogashira reaction/lactonization of methyl2-(2′,2′-dibromovinyl)benzoate with terminal alkynes has been developed. This facile and direct approach furnishes a variety of 3-alkynyl isocoumarins in moderate to good yields under mild reaction conditions. Furthermore, this method enables concise total synthesis of natural products 3′-hydroxycorfin and gymnopalynes