A deeper insight into direct trifluoromethoxylation with trifluoromethyl triflate
摘要:
Commercially available fluorides (silver fluoride and n-tetrabutylammonium triphenyldifluorosilicate), combined with TFMT, allow a simple generation, in situ, of silver and n-tetrabutylammonium trifluoromethoxides which were able to react with electrophilic substrates. Silver trifluoromethoxide, which is usually more efficient than n-tetrabutylammonium trifluoromethoxide, converts, under mild conditions, primary aliphatic bromides and iodides, as well as primary and secondary benzylic or allylic bromides to the corresponding trifluoromethoxylated compounds. Several trifluoromethyl ethers, which could be valuable building-blocks, were prepared in such a way. (C) 2009 Elsevier B.V. All rights reserved.
A mild and highly chemoselective iodination of alcohol using polymer supported DMAP
作者:DIPARJUN DAS、JASHA MOMO H ANAL、LALTHAZUALA ROKHUM
DOI:10.1007/s12039-016-1158-1
日期:2016.11
supported DMAP is used in catalytic amount and is recovered and reused several times. Additionally, this method is highly chemoselective. A mild and highly selective iodination of alcohols using polymer supported 4-(Dimethylamino)pyridine (DMAP) in catalytic amount is reported. The basecatalyst can be easily recovered by simple filtration and reused several times without appreciable loss in activity.
the reagents: the replacement of methyl by isopropyl groups led to a significant increase of reactivity. We then described a unified procedure for all deoxyhalogenations using the readily available α-chloroenamines as reagents with (bromination, iodination) or without (chlorination) an alkaline bromide or iodide. Finally, we showed that deoxyhalogenation reactions of secondary alcohols were highly
Iron(III)-Catalyzed Halogenations by Substitution of Sulfonate Esters
作者:Nuria Ortega、Andrés Feher-Voelger、Margarita Brovetto、Juan I. Padrón、Victor S. Martín、Tomás Martín
DOI:10.1002/adsc.201000740
日期:2011.4.18
A novel halogenation reaction from sulfonates catalyzed by iron(III) is described. The reaction can be performed as a stoichiometric or a catalytic version. This reaction provides a convenient strategy for the efficient access to structurally diverse secondary chlorides, bromides and iodides. The stereochemical course of the reaction is governed by the substrate and the experimental conditions. Secondary
Copper‐Catalyzed Difluoromethylation of Alkyl Iodides Enabled by Aryl Radical Activation of Carbon–Iodine Bonds
作者:Aijie Cai、Wenhao Yan、Chao Wang、Wei Liu
DOI:10.1002/anie.202111993
日期:2021.12.20
An aryl radical activation strategy has been developed that can engage unactivated alkyliodides in copper-catalyzed Negishi-type cross-coupling reactions. The strategy is based on the largely overlooked yet highly efficient reactivity of aryl radicals to abstract iodine atoms from alkyliodides.
Cobalt-Catalyzed Csp<sup>3</sup>–Csp<sup>3</sup> Cross-Coupling of Functionalized Alkylzinc Reagents with Alkyl Iodides
作者:Ferdinand H. Lutter、Lucie Grokenberger、Maximilian Benz、Paul Knochel
DOI:10.1021/acs.orglett.0c00795
日期:2020.4.17
A mild cobalt-catalyzed Negishi-type cross-coupling of various functionalized dialkylzinc reagents with primary and secondary alkyl iodides in acetonitrile is reported using a combination of 20% CoCl2 and chelating nitrogen ligands. The method allows the construction of molecules with alkyl chains bearing sensitive functional groups at room temperature.