BARC/PUB/2022/0977

 
 

Synthesis of 2-Substituted Indoles by Pd-Catalyzed Reductive Cyclization of 1-Halo-2-nitrobenzene with Alkynes

 
     
 
Author(s)

Lokolkar, M. S.; Mane, P. A.; Dey, S.; and others
(ChD)

Source

European Journal of Organic Chemistry, 2022. Vol. 2022: Article no. 202101505

ABSTRACT

An effective process for synthesizing 2-substituted indoles in a one-pot tandem reaction of 1-halo-2-nitrobenzene and terminal alkynes through addition/reductive cyclization is presented. This protocol involves a Sonogashira-type coupling reaction followed by reductive cyclization employing dppf (1,1’-bis(diphenylphosphino)ferrocene) ligated Pd dithiolate complex as a catalyst and Zn as an inexpensive reductant. This efficient and tandem process tolerates broad functional groups with moderate to good yields. The gram-scale synthesis of 2-substituted indole has also been demonstrated. This protocol provides an alternative route for the synthesis of 2-substituted indoles.

 
 
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