Ni-Catalyzed Regioselective C-5 Halogenation of 8-Aminoquinoline and Co-Catalyzed Chelation Assisted C-H Iodination of Aromatic Sulfonamides with Molecular Iodine.

A Ni(II)- and Co(II)-catalyzed sequential iodination of sulfonamides using inexpensive and milder molecular iodine (I 2 ) as an iodinating reagent is reported for the first time. The 8-amino-5-iodoquinoline moiety prepared via nickel catalysis act as a directing group for second iodination by chelation assisted cobalt catalysis resulting in ortho-iodinated arylsulfonamide products. This methodology has been elaborated to various value added products by coupling reactions.