Isoselenazolones as Catalysts for the Activation of Bromine: Bromolactonization of Alkenoic Acids and Oxidation of Alcohols

Isoselenazolones were synthesized by a copper-catalyzed Se–N bond forming reaction between 2-halobenzamides and selenium powder. The catalytic activity of the various isoselenazolones was studied in the bromolactonization of pent-4-enoic acid. Isoselenazolone 9 was studied as a catalyst in several r...

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Bibliographic Details
Published in:Journal of organic chemistry 2012-11, Vol.77 (21), p.9541-9552
Main Authors: Balkrishna, Shah Jaimin, Prasad, Ch Durga, Panini, Piyush, Detty, Michael R, Chopra, Deepak, Kumar, Sangit
Format: Article
Language:English
Subjects:
Catalysis
Catalysts: preparations and properties
Chemistry
Exact sciences and technology
General and physical chemistry
Heterocyclic compounds
Kinetics and mechanisms
Miscellaneous
Noncondensed benzenic compounds
Organic chemistry
Preparations and properties
Reactivity and mechanisms
Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
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Summary:Isoselenazolones were synthesized by a copper-catalyzed Se–N bond forming reaction between 2-halobenzamides and selenium powder. The catalytic activity of the various isoselenazolones was studied in the bromolactonization of pent-4-enoic acid. Isoselenazolone 9 was studied as a catalyst in several reactions: the bromolactonization of a series of alkenoic acids with bromine or N-bromosuccinimide (NBS) in the presence of potassium carbonate as base, the bromoesterification of a series of alkenes using NBS and a variety of carboxylic acids, and the oxidation of secondary alcohols to ketones using bromine as an oxidizing reagent. Mechanistic details of the isoselenazolone-catalyzed bromination reaction were revealed by 77Se NMR spectroscopic and ES-MS studies. The oxidative addition of bromine to the isoselenazolone gives the isoselenazolone(IV) dibromide, which could be responsible for the activation of bromine under the reaction conditions. Steric effects from an N-phenylethyl group on the amide of the isoselenazolone and electron-withdrawing fluoro substituents on the benzo fused-ring of the isoselenazolone appear to enhance the stability of the isoselenazolone as a catalyst for the bromination reaction.
ISSN:0022-3263
1520-6904
DOI:10.1021/jo301486c