Synthesis of Biaryls via a Nickel(0)-Catalyzed Cross-Coupling Reaction of Chloroarenes with Arylboronic Acids
作者:Syun Saito、Saori Oh-tani、Norio Miyaura
DOI:10.1021/jo9707848
日期:1997.11.1
The cross-coupling reaction of arylboronic acid with chloroarenes to give biaryls was carried out in high yields at 70-80 degrees C in the presence of a nickel(0) catalyst and K(3)PO(4) (3 equiv) in dioxane or benzene. The nickel(0) catalyst in situ prepared from NiCl(2).L (L = dppf, 2PPh(3)) (3-10 mol %) and 4 equiv of BuLi at room temperature was recognized to be most effective. The reaction can
Synthesis of Substituted Coumarins via Brønsted Acid Mediated Condensation of Allenes with Substituted Phenols or Anisoles
作者:Sundae Kim、Dongjin Kang、Chang-Hee Lee、Phil Ho Lee
DOI:10.1021/jo301086k
日期:2012.8.3
Coumarins were obtained from the condensation of electron-rich arenes with allenes in the presence of TfOH in good yield. Depending on the substituent pattern of allenes employed, the general synthetic method of 4-substituted and 3,4-disubstituted 3-arylcoumarins has been developed. Readily available allenes were employed as the three-carbon atom sources constituting the coumarin skeleton.