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Hypervalent iodine oxidizing agent, cf Iodosobenzene diacetate, B24531. PIFA oxidizes hydroquinones and catechols to benzoquinones. In the presence of a nucleophile, 4-substituted phenols give the corresponding 4,4-disubstituted cyclohexadienone: J. Chem. Soc., Perkin 1, 1891 (1993); 2047 (1994), and refs. therein. In water, 1,4-dimethoxy aromatics undergo oxidative demethylation to p-quinones: Tetrahedron Lett., 42, 6899 (2001). In TFA, acetanilides can be hydroxylated in the p-position: J. Org. Chem., 67, 7424 (2002).• Terminal alkynes are oxidized by PIFA to ɑ-hydroxy ketones: Tetrahedron Lett., 26, 3837 (1985).
• Primary amides undergo a Hofmann-like rearrangement to amines, avoiding the harsh conditions often required for the classical method: J. Org. Chem., 49, 4272, 4277 (1984); Synth. Commun., 18, 1615 (1988); Org. Synth. Coll., 8, 132 (1993). Promotes the azidation of alkyl groups of p-alkylanisoles with TMS azide: Tetrahedron Lett., 32, 4321 (1991); J. Am. Chem. Soc., 116, 3684 (1994); Synlett, 427 (1994), and also the direct nucleophilic sulfenylation and thiocyanation of phenol ethers with thiols and TMS isothiocyanate respectively: Synlett, 211 (1995); J. Org. Chem., 60, 7144 (1995).
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Mediates the selective cyanation of electron-rich aromatics with Trimethylsilyl cyanide, A19598, e.g. indoles to 2-cyanoindoles: Org. Lett., 7, 537 (2005).• For a brief feature on uses of this reagent in synthesis, see: Synlett, 2851 (2006). For a comprehensive review of polyvalent iodine compounds, see: Chem. Rev., 96, 1123 (1996).
刺激性 (Xi)