Proton transfer process in synthesis of 3-acetyl-4-(substituted ethylenyl)coumarins and chromeno[3,4-c]pyridines
作者:Abdolali Alizadeh、Reza Mohammadi、Fahimeh Bayat、Long-Guan Zhu
DOI:10.1016/j.tet.2018.03.015
日期:2018.4
3-acetylcoumarins in dichloromethane afford functionalized 3-acetyl-4-(substituted ethylenyl)coumarins. Also, triphenylphosphine-catalyzed three-component cascade annulation reactions of 3-acetylcoumarins, activated acetylenic compounds, and hydrazines or amines provide a straightforward access to 3,5-dihydro-2H-chromeno[3,4-c]pyridine-1,2-dicarboxylates. In these strategies, the main step to the target products
缺电子的碳-碳三键与3-乙酰香豆素在二氯甲烷中的三苯基膦介导的反应提供了功能化的3-乙酰基-4-(取代的乙烯基)香豆素。此外,三苯基膦催化的3-乙酰香豆素,活化的炔属化合物以及肼或胺类的三组分级联环合反应可直接获得3,5-二氢-2 H -chromeno [3,4- c ]吡啶-1, 2-二羧酸盐。在这些策略中,目标产品的主要步骤是质子转移过程。所有产品均以高至高收率获得。