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This study provides a greener peptide coupling method using triarylphosphine and recyclable bicyclic benziodazolone, which acts as an oxidant for phosphine as well as base. 

2-Iodosylbenzoic acid in the presence of trifluoromethanesulfonic anhydride is an efficient oxidant and electrophilic reagent useful for preparation of the corresponding alkenyl and aryliodonium salts. Compared to the previously reported methods of electrophilic activation of 2-iodosylbenzoic acid, this procedure is compatible with acid-sensitive functional groups, requires mild reaction conditions, and affords products in higher yields. 

Hypervalent iodine heterocycles represent one of the important classes of hypervalent iodine reagents with many applications in organic synthesis. This paper reports a simple and convenient synthesis of benziodazolones by the reaction of readily available iodobenzamides with m-chloroperoxybenzoic acid in acetonitrile at room temperature. The structure of one of these new iodine heterocycles was confirmed by X-ray analysis. In combination with PPh3 and pyridine, these benziodazolones can smoothly react with alcohols or amines to produce the corresponding esters or amides of 3-chlorobenzoic acid, respectively. It was found that the novel benziodazolone reagent reacts more efficiently than the analogous benziodoxolone reagent in this esterification. 

Abstract Hypervalent iodine compounds have found broad application in modern organic chemistry as reagents and catalysts. Cyclic hypervalent iodine reagents based on the benziodoxole heterocyclic system have higher stability compared to their acyclic analogues, which makes possible the preparation and safe handling of the reagents with special ligands such as azido, cyano, and trifluoromethyl groups. Numerous iodine‐substituted benziodoxole derivatives have been prepared and utilized as reagents for transfer of the substituent on hypervalent iodine to organic substrate. Reactions of these reagents with organic substrates can be performed under metal‐free conditions, in the presence of transition metal catalysts, or using photocatalysts under photoirradiation conditions. In this review, we focus on the most recent synthetic applications of cyclic hypervalent iodine(III) reagents with the following ligands: N₃, NHR, CN, CF₃, SCF₃, OR, OAc, ONO₂, and C(=N₂)CO₂R. The review covers literature published mainly in the last 5 years. 

Organohypervalent iodine reagents are widely used for the preparation of various oxazolines, oxazoles, isoxazolines, and isoxazoles. In the formation of these heterocyclic compounds, hypervalent iodine species can serve as the activating reagents for various substrates, as well as the heteroatom donor reagents. In recent research, both chemical and electrochemical approaches toward generation of hypervalent iodine species have been utilized. The in situ generated active species can react with appropriate substrates to give the corresponding heterocyclic products. In this short review, we summarize the hypervalent-iodine­-mediated preparation of oxazolines, oxazoles, isoxazolines, and isoxazoles starting from various substrates. 1 Introduction 2 Synthesis of Oxazolines 3 Synthesis of Oxazoles 4 Synthesis of Isoxazolines 5 Synthesis of Isoxazoles 6 Conclusion