硼酸已成为现代有机合成中最普遍的试剂类别之一,通过C-B 键断裂显示出各种反应特性。在此,我们描述了利用一种现成的硼酸作为氢氧化物的有效替代物,通过激活氟化物络合。开发了迄今为止未知的芳炔诱导的环硫化物开环反应和氟氮杂芳烃的三组分偶联反应,以举例说明其应用价值。与金属氢氧化物或水不同,这种新型羟基源显示出温和的活化条件、良好的功能耐受性和结构可调性,这将产生一种新的合成范式,并在广泛的背景下为有机硼化学提供新的蓝图。详细的计算研究还识别了氟化物激活模式,提供了对前所未有的机制途径的深入见解,并阐明了 ArB(OH) x F y配合物的反应性差异,这充分支持了实验数据。
Direct Synthesis of 4-Quinolones via Copper-Catalyzed Anilines and Alkynes
作者:Xuefeng Xu、Xu Zhang
DOI:10.1021/acs.orglett.7b02495
日期:2017.9.15
and direct approach for constructing 4-quinolones from simple and readily available anilines and alkynes is described. Under the optimal conditions, both N-alkyl- and N-aryl-substituted anilines can be successfully transformed into the corresponding 4-quinolones. This reaction is characterized by mild reaction conditions, high functional-group tolerance, and amenability to gram-scale synthesis.
The Buchwald–Hartwig coupling/Michael addition sequence has been successfully applied to the synthesis of functionalized 1,2-disubstituted 4-quinolones using Pd(OAc)2 as a catalyst and PPh3 as a ligand. Under these conditions, the intermediate products first formed from chalcones and primaryamines underwent catalytic dehydrogenation to yield the 1,2-disubstituted 4-quinolones.