Rhodium‐Catalyzed Intramolecular Cyclization and Rearrangement of 1‐Azido‐2‐(2,2‐Dihalovinyl)arenes and 1‐Azido‐2‐[(2,2‐Dihalovinyl)(Boc)amino]arenes for the Preparation of 2,3‐Dihaloindoles and 2‐Haloquinoxalines

Abstract

AbstractTreatment of 1‐azido‐2‐(2,2‐dihalovinyl)arenes with a catalytic amount of Rh2(esp)2 afforded various 2,3‐dihaloindoles in 51–74% yields. This reaction progressed via the intramolecular cyclization of rhodium nitrene generated in situ and the rearrangement of one halogen group. For the 2‐chloro‐2‐iodovinyl group, the iodo group selectively rearranged to yield 2‐chloro‐3‐iodoindoles as single isomers. Moreover, 1‐azido‐2‐[(2,2‐dihalomovinyl)(Boc)amino]arenes were reacted with a catalytic amount of Rh2(oct)4, which produced 2‐haloquinoxaline in 55–92% yields.