A palladium-catalyzed Barluenga cross-coupling – Reductive cyclization sequence to substituted indoles
作者:S.M. Ashikur Rahman、Björn C.G. Söderberg
DOI:10.1016/j.tet.2021.132331
日期:2021.8
A short and flexible synthesis of substituted indoles employing two palladium-catalyzed reactions, a Barluenga cross-coupling of p-tosylhydrazones with 2-nitroarylhalides followed by a palladium–catalyzed, carbon monoxide–mediated reductive cyclization has been developed. A one-pot, two-step methodology was further developed, eliminating isolation and purification of the cross-coupling product. This
使用两个钯催化的反应,对甲苯磺酰腙与 2-硝基芳基卤化物的Barluenga交叉偶联,然后是钯催化的一氧化碳介导的还原环化反应,一种短而灵活的取代吲哚合成方法已经被开发出来。进一步开发了一锅两步法,消除了交叉偶联产物的分离和纯化。这是通过使用最初添加的 0.025 当量的双(三苯基膦)二氯化钯来实现的,因此在交叉偶联和还原环化中起双重作用。发现在 Barluenga 反应完成后添加 1,3-双(二苯基膦基)丙烷和一氧化碳在大多数情况下提供显着更好的总产率。