Hypervalent Iodine-Induced Nucleophilic Substitution of para-Substituted Phenol Ethers. Generation of Cation Radicals as Reactive Intermediates

Formal Synthesis of (±)-Allocolchicine Via Gold-Catalysed Direct Arylation: Implication of Aryl Iodine(III) Oxidant in Catalyst Deactivation Pathways

“…5), and indeed catalyst loading. Highly electron-rich arenes are known to react with iodine(III) oxidants, such as PIFA, to form diaryliodonium salts, π-complexes or radical cations [17]. Careful in situ analysis of the reactions of 3, 11 and 18e by 1 H NMR indicated that 22a-c are diaryliodonium salts; this was subsequently confirmed by mass spectrometry.…”

Iodine(III)-Mediated Ring Contraction Reactions: Synthesis of Oxygen- and Nitrogen-Substituted Indanes

“…41,42 The generation of these cation radicals could be a possible reason of rearrangement failure in substrates like 1b, due to their susceptibility towards nucleophilic attack and other side reactions. Thus, we consider that the ring contraction could take place with an acetyl group instead of a methoxy making it useful in the synthesis of oxygen-substituted indanes.…”

Development and Application of New Oxidation Systems Utilizing Oxometalate Catalysts

“…The spectrum thus obtained was almost identical to that reported previously by us. 86) Additionally, UV spectrum of the reaction of dimethoxybenzene under the same reagent system also showed cation radical species which can be rationalized by absorption band between 400 and 600 nm (Chart 1b). 86) When HPA in the absence of PhI(OCOCF 3 ) 2 was used in these reactions, no cation radical species, could be observed in both UV and ESR spectra.…”

“…Since the early 1980s, Kita and coworkers have revealed a wide array of reactivities for trivalent iodine reagents, such as phenyliodine(III) diacetate (PhI(OAc) 2 , PIDA or DIB), phenyliodine(III) bis(trifluoroacetate) (PhI(OCOCF 3 ) 2, PIFA or BIT), and they have developed many effective oxidation tools in organic synthesis. Among these results, the single-electron-transfer (SET) oxidation method of electron-rich arenas using PhI(OCOCF 3 ) 2 in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) 86) or PhI(OCOCF 3 ) 2 -BF 3 ·Et 2 O in CH 2 Cl 2 92) is one of the most important works, and this method was applied to the synthesis of several biologically active natural products. In this work, we tried to utilize PhI(OCOCF 3 ) 2 -HPA combination to design new oxidation systems via SET reaction.…”