- Controlled α-mono- and α,α-di-halogenation of alkyl sulfones using reagent-solvent halogen bonding
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The direct and selective α-mono-bromination of alkyl sulfones was achieved through base-mediated electrophilic halogenation. The appropriate combination of solvent and electrophilic bromine source was found to be critical to control the nature of the products formed, where reagent-solvent halogen bonding is proposed to control the selectivity via alteration of the effective size of the electrophilic bromine source. Conversely, the α,α-di-brominated sulfones were selectively obtained in good yields following polyhalogenation followed by selective de-halogenation during workup. Both procedures can be applied on gram scale, and the mono-halogenation was successfully extended to the fully selective α-chlorination, α-iodination and α-fluorination of alkyl sulfones.
- Poteat, Christopher M.,Lindsay, Vincent N. G.
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supporting information
p. 2912 - 2915
(2019/03/17)
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- Chemoselective mono halogenation of β-keto-sulfones using potassium halide and hydrogen peroxide; synthesis of halomethyl sulfones and dihalomethyl sulfones
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The synthesis of α-halo β-keto-sulfones using potassium halide and hydrogen peroxide as a chemoselective mono halogenation reagent and the synthesis of α,α-symmetrical and asymmetrical dihalo β-keto-sulfones and α-halo, α-alkyl and β-keto-sulfones is described. Base induced cleavage of α-halo β-keto-sulfones, α,α-dihalo β-keto-sulfones, and α-halo, α-alkyl β-keto-sulfones afforded the corresponding halomethyl sulfones, dihalomethyl sulfones and haloalkyl sulfones.
- Suryakiran,Prabhakar,Srikanth Reddy,Chinni Mahesh,Rajesh,Venkateswarlu
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p. 877 - 881
(2007/10/03)
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- THE PREPARATION, SPECTRAL PROPERTIES, STRUCTURES, AND BASE-INDUCED CLEAVAGE REACTIONS OF SOME α-HALO-β-KETOSULFONES
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The halogenation of β-ketosulfones such as α-methylsulfonylacetophenone (1) and benzenesulfonylacetone (10) can be effected with sulfuryl chloride or pyridinium bromide perbromide.Regiochemical control can be achieved by control of stoichiometry and/or the reaction conditions.Detailed 1H and 13C nmr, and mass spectra are recorded for a series of halogenated β-ketosulfones, together with structures by X-ray crystallography for 1, 2-chloro-2-methylsulfonyl-1-phenylethanone (2), chloromethyl methyl sulfone (4), and α-chloroacetophenone (21).Results from these studies are used to suggest a reason for the difficulty associated with substitution reactions of α-halosulfones.
- Grosset, Stuart J.,Dubey, Pramod K.,Gill, Glen H.,Cameron, Stanley T.,Gardner, Patrick A.
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p. 798 - 807
(2007/10/02)
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- Vicarious Nucleophilic Substitution of Hydrogen in Nitroarenes with Carbanions of α-Haloalkyl Phenyl Sulfones
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Carbanions of α-chloroalkyl phenyl sulfones and N,N-dialkyl-α-chloroalkanesulfonamides react with nitrobenzenes to effect direct nucleophilic replacement of hydrogen ortho and para to the nitro group, with vicarious loss of chloride anion, to give the corresponding nitrobenzylsulfonyl derivatives.The reaction occurs much more rapidly than the replacement of such good leaving groups as halogen, methoxy, and phenoxy.Most substituents in the nitrobenzene ring do not interfere with the reaction.The effect of substituents in the nitrobenzene and the carbanion on the orientation of the substitution is discussed.
- Makosza, Mieczyslaw,Golinski, Jerzy,Baran, Janusz
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p. 1488 - 1494
(2007/10/02)
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