Cy<sub>2</sub>NH·HX-Promoted Cyclizations of <i>o</i>-(Alk-1-ynyl)benzoates and (<i>Z</i>)-Alk-2-en-4-ynoate with Copper Halides to Synthesize Isocoumarins and α-Pyrone
作者:Jin-Heng Li、Yun Liang、Ye-Xiang Xie
DOI:10.1055/s-2006-958960
日期:2007.2
Cy 2 NH·HX was found to improve the cyclization reactions of o-(alk-1 -ynyl)benzoates and (Z)-alk-2-en-4-ynoate with CuX 2 (X = Cl, Br) to synthesize the corresponding 4-haloisocoumarins and 5-bromo-2-pyrone, respectively. In the presence of two equivalents of CuCl 2 , cyclization of methyl 2-(2-phenylethynyl)benzoate was conducted smoothly to afford the corresponding desired product in 83% yield after
Cy 2 NH·HX 可改善邻-(alk-1-ynyl)benzoate 和 (Z)-alk-2-en-4-ynoate 与 CuX 2 (X = Cl, Br) 的环化反应,合成分别对应的 4-卤代异香豆素和 5-溴-2-吡喃酮。在两当量的CuCl 2 存在下,2-(2-苯基乙炔基)苯甲酸甲酯的环化反应顺利进行,24小时后得到相应的所需产物,收率83%,而8小时内收率提高到91%。添加0.1当量的Cy 2 NH·HCl。在标准反应条件下,多种邻-(alk-1-ynyl)benzoate和(Z)-alk-2-en-4-ynoate与CUX 2发生环化反应,得到相应的4-卤代异香豆素和5-溴-2-吡喃酮,分别以中等至极好的产量。