The selective synthesis of 3-halogenated quinolin-2-ones from N-arylpropynamides was realized via umpolung process mediated by phenyliodine(III) diacetate (PIDA) and MX (LiCl, LiBr, CuI). Differing from most previous electrophilic cyclization/halogenation processes that afforded spiro[4,5]trienones, 3-halogenated quinolin-2-ones were obtained through this method with high selectivity.

An interrupted Pummerer reaction of PhICl 2 and sulfoxides was found to in situ generate reactive organosulfenyl chloride, which enabled the intramolecular electrophilic cyclization of 2-alkynylanilines, generating 3-sulfenylated indole with a good to excellent yield under metal-free conditions. One striking feature of the approach is that sulfoxide regeneration can be realized via the oxidation of the formed sulfides by the generated hypervalent iodine species.

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A metal-free sulfenylation/spirocyclization of indolyl-ynones realized by organosulfenyl chloride, generated in situ from the reaction of disulfides and PhICl2, is presented. This cascade one-pot process enables a chemoselective synthesis of diverse sulfenylated spiroindolenines depending on the substituent pattern at the two-position of indolyl-ynones.

Treatment of thioacetals and thioketals with iodosobenzene in anhydrous DCM conveniently afforded the corresponding carbonyl compounds in high yields under water-free conditions. The mechanistic studies indicate that this dethioacetalization/dethioketalization process does not need water and the oxygen of the carbonyl products comes from the hypervalent iodine reagent.