- Direct C-H α-Arylation of Enones with ArI(O2CR)2 Reagents
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α-Arylation of α,β-unsaturated ketones constitutes a powerful synthetic transformation. It is most commonly achieved via cross-coupling of α-haloenones, but this stepwise strategy requires prefunctionalized substrates and expensive catalysts. Direct enone C-H α-arylation would offer an atom- and step-economical alternative, but such reports are scarce. Herein we report the metal-free direct C-H arylation of enones mediated by hypervalent iodine reagents. The reaction proceeds via a reductive iodonium Claisen rearrangement of in situ-generated β-pyridinium silyl enol ethers. The aryl groups are derived from ArI(O2CCF3)2 reagents, which are readily accessed from the parent iodoarenes. The reaction is tolerant of a wide range of substitution patterns, and the incorporated arenes maintain the valuable iodine functional handle. Mechanistic investigations implicate arylation via an umpoled "enolonium" species and show that the presence of a β-pyridinium moiety is critical for the desired C-C bond formation.
- Sousa E Silva, Felipe Cesar,Van, Nguyen T.,Wengryniuk, Sarah E.
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supporting information
p. 64 - 69
(2020/01/22)
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- Flow Synthesis of Iodonium Trifluoroacetates through Direct Oxidation of Iodoarenes by Oxone
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Flow chemistry is considered to be a versatile and complementary methodology for the preparation of valuable organic compounds. We describe a straightforward approach for the synthesis of iodonium trifluoroacetates through the direct oxidation of iodoarenes in a simple flow reactor using an Oxone-filled cartridge. Optimization has been carried out using the Nelder–Mead algorithm. The procedure allows a wide range of iodonium salts to be prepared from simple starting materials.
- Soldatova, Natalia S.,Postnikov, Pavel S.,Yusubov, Mekhman S.,Wirth, Thomas
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p. 2081 - 2088
(2019/03/11)
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- Facile One-Pot Synthesis of Diaryliodonium Salts from Arenes and Aryl Iodides with Oxone
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A straightforward synthesis of diaryliodonium salts is achieved by using Oxone as the stoichiometric oxidant. Slow addition is the key to obtaining good yields and purities of the reaction products, which are highly useful reagents in many different areas of organic synthesis.
- Soldatova, Natalia,Postnikov, Pavel,Kukurina, Olga,Zhdankin, Viktor V.,Yoshimura, Akira,Wirth, Thomas,Yusubov, Mekhman S.
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- Direct and convenient synthesis of [bis(trifluoroacetoxy)iodo]arenes from iodoarenes
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An easy, safe, and effective method for preparing [bis-(trifluoroacetoxy) iodo]arenes, ArI(OCOCF3)2, in high yields from some iodoarenes are reported, using a K2S2O8/CF 3COOH/CH2Cl2 system. This procedure avoids the use of high temperature and severe reaction conditions.
- Hossain, Delwar,Kitamura, Tsugio
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p. 142 - 144
(2007/10/03)
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- Easy preparation of [bis(trifluoroacetoxy)iodo]arenes from iodoarenes, with sodium percarbonate as the oxidant
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Easy and effective preparations of the nearly pure [bis(trifluoroacetoxy) iodo]arenes, ArI(OCOCF)3, from some iodoarenes, ArI, are reported, using an anhydrous) sodium (percarbonate/(CF3CO)2O/CH 2Cl2 system. The colorless, freshly prepared (ArI(OCOCF)3)2 thus obtained were 98-99% pure (by iodometry).
- Kazmierczak, Pawel,Skulski, Lech
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p. 810 - 812
(2007/10/03)
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