An efficient and highly functional group compatible procedure for controllable transformation of indoles by the combination of phenyliodine bis(trifluoroacetate) (PIFA) with n-Bu4NCl·H2O (TBAC) is exploited. Through controlling the amount of PIFA and TBAC from one to three equivalents, the 3-chloro-indoles, 3-chloro-2-oxindoles and 3,3-dichloro-2-oxindoles are obtained respectively in good to excellent yields. The advantages of the protocol include mild conditions, short reaction time, easy and simple to handle, high yields, good functional group tolerance, and using air- and moisture-stable promoter (PIFA). The mechanism studies show that the reaction may proceed through halonium ion species mediated halogenation-elimination-halogenation stepwise process.

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