Abstract The treatment of 1-methylindole-2, 3-dicarboxylic acid with hypervalent iodine (III) reagent, phenyliodine diacetate (PIDA), in the presence of lithium bromide gave 1-methyl-3, 3-dibromooxindole. However, the reaction of 1-(phenylsulfonyl) indole-2, 3-dicarboxylic acid with PIDA in the presence of lithium bromide afforded 2, 3-dibromo-1-(phenylsulfonyl) indole. In a similar manner, the 2, 3-dichloro-and 2, 3-diiodo-indole derivatives were ...