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We present herein a computational exploration into the mechanism and origin of the reactivity difference between N‐triflylimino‐λ3‐iodane and N‐triflylimino‐λ3‐bromane in the C−H amination and alkene aziridination. Our calculations revealed that the preferred mechanism for C−H amination involves the generation of free nitrene intermediate, while the alkene aziridination proceeds via a concerted reaction mechanism. The superior reactivity of N‐triflylimino‐λ3‐bromane over N‐triflylimino‐λ3‐iodane could be mainly ascribed to better nucleofugality of the bromanyl moiety, which can be characterized by the strength of I−N and Br−N bond. The effect of solvent polarity on the reactivity of N‐triflylimino‐λ3‐bromane as a nitrene precursor will be discussed. [ABSTRACT FROM AUTHOR]

The quantitative Lewis acidity of N‐heterocyclic iod(az)olium salts is helpful for their further application in organic chemistry. The acidity scales of different N‐Heterocyclic iodonium salts (NHISs) in acetonitrile are investigated using Density functional theory (DFT) studies. There are a total of 121N‐Heterocyclic iodonium salts that have been designed by combining N‐heterocyclic and iodonium salt structures in this research. Theoretical calculations systematically established the 31P NMR chemical shifts of NHISs, and the relative Lewis acidity scale was derived. The Lewis acidity trend is analyzed and explained by the natural population analysis (NPA) charges, molecular electrostatic potential, and the interaction between the iodonium center and the N‐heterocyclic substituents. This study is expected to provide a practical quantitative theoretical scale for the understanding and design of hypervalent iodine(III) reagents with versatile Lewis acidity. [ABSTRACT FROM AUTHOR]

An oxidative cyclization of electron‐rich α‐arylhydrazones promoted by phenyliodine bis(trifluoroacetate) (PIFA) has been accomplished. This metal‐free, chemoselective transformation allows to obtain synthetically and medicinally important N‐amino‐1H‐indoles, obviating the need for pre‐functionalization of substrates. [ABSTRACT FROM AUTHOR]

A series of novel fluoro‐containing hypervalent iodane (III) reagents was designed and synthesized. By employing these novel hypervalent iodane (III) reagents, an efficient visible‐light‐triggered radical cyclization of alkynoates to diversely 3‐fluoroalkylated coumarins was developed under metal free condition. It provided an alternative and environmental friendly approach for the installation of 3‐fluoroalkyl motif into synthetically valuable building block coumarins. [ABSTRACT FROM AUTHOR]

A visible light‐induced radical ipso‐difluoromethylation of N‐arylpropiolamides to synthesize 3‐difluoromethyl spiro[4.5]trienones was developed for the first time. In this transformation PhI(O2CCHF2)2 was used as difluoromethylation reagent and PhI(OAc)2 was employed as oxidant. Due to the cheap and readily accessible reagents and oxidant as well as the mild reaction conditions, this method is as an efficient and practical strategy for the synthesis of difluoromethyl‐substituted spiro[4.5]trienones. [ABSTRACT FROM AUTHOR]

The modification of quinoxalin-2(1H)-ones via direct C-H bond functionalization has begun to receive widespread attention, due to quinoxalin-2(1H)-one derivatives' various biological activities and pharmaceutical properties. This mini review concentrates on the accomplishments of arylation, trifluoromethylation, alkylation, and alkoxylation of quinoxalin-2(1H)-ones with hypervalent iodine(III) reagents as reaction partners or oxidants. The reaction conditions and mechanisms are compared and discussed in detail.

1-Benzoyloxy-1,2-benziodoxol-3-(1H)-one (IBA-OBz), a readily available and bench stable benziodoxole-based iodine(III) reagent, can be employed for the synthesis of dipeptides from various standard and sterically hindered amino acids in the presence of (4-MeOC6H4)3P. The combined system of IBA-OBz/(4-MeOC6H4)3P is also successfully applied to the solid-phase peptide synthesis and a pentapeptide leu-enkephalin in unprotected form has been synthesized. Density functional theory calculations reveal that the rate-limiting step is nucleophilic attack of 4-dimethylaminopyridine (DMAP) onto IBA-OBz.

The system of the hypervalent iodine(III) reagent FPID and (4-MeOC6H4)3P was successfully applied to solid-phase peptide synthesis and cyclic peptide synthesis. Four peptides with biological activities were synthesized through SPPS and the bioactive cyclic heptapeptide pseudostellarin D was obtained via solution-phase peptide synthesis. It is worth noting that FPID can be readily regenerated after the peptide coupling reaction.

Sulfoximidoyl‐containing 1,2‐benziodoxoles add to styrenes by a photoredox radical process affording difunctionalized products with high regioselectivity. The solvent plays a significantly role in the reaction path, in which Eosin Y appears to have a dual role rendering the process diastereoselective. With Eosin Y as the photocatalyst, sulfoximidoyl‐substituted 1,2‐benziodoxoles add to double bonds of styrene derivatives. The process is highly regioselective providing difunctionalized products with remarkable diastereoselectivities. The H‐bond capabilities of the organic photocatayst appear to play an important role in the selectivity‐determining step of the process. [ABSTRACT FROM AUTHOR]

Abstract: A series of N‐alkoxyindole‐3‐carbonitriles were synthesized, under mild conditions, via intramolecular heterocyclization of the readily available 3‐alkoxyimino‐2‐arylalkylnitriles mediated by iodobenzene dichloride/zinc chloride. The mechanism of the reaction proposes the formation of a key intermediate of nitrenium cation from a chlorination and dechlorination process facilitated by the hypervalent iodine reagent and Lewis acid respectively. [ABSTRACT FROM AUTHOR]

Hypervalent iodine(III) reagents have been vastly used in many useful organic transformations. In this review article, we highlight the strategies that used the common hypervalent iodine(III) reagents as oxidants to synthesize the heterocyclic compounds, based on the patterns of bond formation during the construction of the heterocyclic backbones. [ABSTRACT FROM AUTHOR]

A novel oxidative cycloisomerization of cis-enynols has been developed using a combination of hypervalent iodine(III) reagent, molecular iodine, and a base. This method offers an efficient synthesis of 2-acyl furans with diverse substitution patterns in a �regioselective manner under mild reaction conditions. A mechanistic proposal for these transformations involving alkyne activation by trifluoroacetylhypoiodite generated in situ is presented. [ABSTRACT FROM AUTHOR]

[Display omitted] A visible light-induced radical difluoromethylation of N -allylbenzamide by [bis(difluoroacetoxy)iodo]benzene to prepare difluoromethylated dihydroisoquinolinones was developed for the first time. To facilitate the oxidative aromatization step, PhI(OAc) 2 was employed as oxidant. The inexpensive and readily accessible reagents and the mild reaction conditions render this method an efficient and practical strategy for the synthesis of difluoromethylated dihydroisoquinolinones. [ABSTRACT FROM AUTHOR]

Abstract: The hypervalent iodine(III) reagent, phenyliodine bis(trifluoroacetate) (PIFA)-mediated oxidative nucleophilic substitution of electron-rich aromatics involving aromatic cation radical intermediates was utilized in the direct aromatic carbon–oxygen bond formation reaction, and a novel and simple synthetic method for chroman derivatives was developed. As an extension of this methodology, a facile access to spirodienone derivatives was also achieved. [Copyright &y& Elsevier]

• A visible-light induced aryldifluoromethylation of N- arylacrylamides was achieved. • Inexpensive and readily accessible [bis(difluoroacetoxy)iodo]benzene was used. • No photo-catalyst was used. • The synthesis of difluoromethyl substituted oxindoles was achieved. Visible light-induced radical aryldifluoromethylation of N -arylacrylamides using [bis(difluoroacetoxy)iodo]benzene as a difluoromethylation reagent is reported for the first time. The inexpensive and readily accessible reagents and the mild reaction conditions render this method an alternative and practical strategy for the synthesis of difluoromethyl substituted oxindoles. [ABSTRACT FROM AUTHOR]