Search for: All records

Abstract Organic azides have found wide application in various fields of science and technology. This review summarizes recently developed approaches to the direct, one‐step synthesis of diverse organic azides utilizing hypervalent iodine reagents. The first part of review deals with the azidation using unstable azidoiodinanes generatedin situfrom common hypervalent iodine reagents (such as diacetoxyiodobenzene or iodosylbenzene) and a source of azide anion (TMSN₃or NaN₃). The second part of review is dedicated to the application of stable azidobenziodoxoles as useful azidating reagents that allow selective direct azidation of C−H bonds or double carbon‐carbon bonds under mild reaction conditions. The use of azidobenziodoxoles eliminates the main disadvantages of the traditional approaches to organic azides, such as the need in pre‐functionalization of organic substrates and harsh reaction conditions. Synthetic application of azidobenziodoxoles made possible direct selective azidation of a plethora of organic substrates including complex molecules at the late synthetic stage. 

Abstract Pseudocyclic β‐trifluorosulfonyloxy vinylbenziodoxolones were prepared starting from hydroxybenziodoxolones and alkynes in the presence of trifluoromethanesulfonic acid. The reaction of these compounds with azide anion leads to β‐azido vinylbenziodoxolones as products of vinylic nucleophilic substitution in which addition‐elimination reactions occur and the double bond configuration is retained. The structures of β‐trifluorosulfonyloxy vinylbenziodoxolone and β‐azido vinylbenziodoxolone were established by single crystal X‐ray diffraction. magnified image 

Abstract Aiming at the enhanced catalytic activity of fluoro‐λ³‐iodane generated from iodoarene precatalyst with Selectfluor and HF⋅pyridine, this study focused on the λ³‐iodanes bearing coordinating substituents. Compared to 4‐iodoanisole as a precatalyst of our previous method,N‐methyl‐2‐iodobenzamide or 2‐iodobenzamide worked well in the fluorocyclization ofN‐propargyl carboxamides to oxazoles. Control experiments suggest the equilibrium mixture of iodane‐amine complexes and cyclic iodane fluorides would be involved in the present catalysis. magnified image 

Hypervalent iodine reagents are in high current demand due to their exceptional reactivity in oxidative transformations, as well as in diverse umpolung functionalization reactions. Cyclic hypervalent iodine compounds, known under the general name of benziodoxoles, possess improved thermal stability and synthetic versatility in comparison with their acyclic analogs. Aryl-, alkenyl-, and alkynylbenziodoxoles have recently received wide synthetic applications as efficient reagents for direct arylation, alkenylation, and alkynylation under mild reaction conditions, including transition metal-free conditions as well as photoredox and transition metal catalysis. Using these reagents, a plethora of valuable, hard-to-reach, and structurally diverse complex products can be synthesized by convenient procedures. The review covers the main aspects of the chemistry of benziodoxole-based aryl-, alkynyl-, and alkenyl- transfer reagents, including preparation and synthetic applications. 

Abstract Hypervalent iodine (HVI) reagents have gained much attention as versatile oxidants because of their low toxicity, mild reactivity, easy handling, and availability. Despite their unique reactivity and other advantageous properties, stoichiometric HVI reagents are associated with the disadvantage of generating non-recyclable iodoarenes as waste/co-products. To overcome these drawbacks, the syntheses and utilization of various recyclable hypervalent iodine reagents have been established in recent years. This review summarizes the development of various recyclable non-polymeric, polymer-supported, ionic-liquid-supported, and metal–organic framework (MOF)-hybridized HVI reagents. 1 Introduction 2 Polymer-Supported Hypervalent Iodine Reagents 2.1 Polymer-Supported Hypervalent Iodine(III) Reagents 2.2 Polymer-Supported Hypervalent Iodine(V) Reagents 3 Non-Polymeric Recyclable Hypervalent Iodine Reagents 3.1 Non-Polymeric Recyclable Hypervalent Iodine(III) Reagents 3.2 Recyclable Non-Polymeric Hypervalent Iodine(V) Reagents 3.3 Fluorous Hypervalent Iodine Reagents 4 Ionic-Liquid/Ion-Supported Hypervalent Iodine Reagents 5 Metal–Organic Framework (MOF)-Hybridized Hypervalent Iodine Reagents 6 Conclusion 

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. 

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.