Recent Progress in Synthetic Applications of Hypervalent Iodine(III) Reagents

Hypervalent iodine(III) compounds have found wide application in modern organic chemistry as environmentally friendly reagents and catalysts. Hypervalent iodine reagents are commonly used in synthetically important halogenations, oxidations, aminations, heterocyclizations, and various oxidative functionalizations of organic substrates. Iodonium salts are important arylating reagents, while iodonium ylides and imides are excellent carbene and nitrene precursors. Various derivatives of benziodoxoles, such as azidobenziodoxoles, trifluoromethylbenziodoxoles, alkynylbenziodoxoles, and alkenylbenziodoxoles have found wide application as group transfer reagents in the presence of transition metal catalysts, under metal-free conditions, or using photocatalysts under photoirradiation conditions. Development of hypervalent iodine catalytic systems and discovery of highly enantioselective reactions using chiral hypervalent iodine compounds represent a particularly important recent achievement in the field of hypervalent iodine chemistry. Chemical transformations promoted by hypervalent iodine in many cases are unique and cannot be performed by using any other common, non-iodine-based reagent. This review covers literature published mainly in the last 7-8 years, between 2016 and 2024.

Thermal Nickel-Catalyzed N-Arylation of NH-Sulfoximines with (Hetero)aryl Chlorides Enabled by PhPAd-DalPhos Ligation

We report a versatile method for cross-coupling of NH-sulfoximines with (hetero)aryl chlorides, as well as bromide and sulfonate electrophiles, that makes use of the air-stable, commercial precatalyst (PhPAd-DalPhos)Ni(o-tol)Cl. Under optimized conditions a diverse electrophile scope is established, including the N-arylation of the pharmaceutical Clozapine. While 5 mol % Ni and 80 °C are commonly employed in this chemistry, successful examples utilizing 1 mol % Ni and/or 25 °C are presented. Competition experiments establish the superiority of NH-sulfoximine over primary sulfonamide as nucleophiles under these conditions.

In-silico investigation of 4-nitro-N-1H-pyrazol-3-ylbenzamide towards its potential use against SARS-CoV-2: a DFT, molecular docking and molecular dynamics study

In the present research work, we report the synthesis and characterization of novel pyrazole derivative obtained by the condensation reaction of 4-nitro benzaldehyde group with one equivalent of the 2-amino pyrazole yielding 4-nitro-N-1H-pyrazol-3-ylbenzamide with high yield. The two symmetry-independent molecules (molecule A and molecule B) differ about the central C-N bond, with the dihedral angles between the pyrazole ring system and the nitrobenzene ring being 13.90° and 18.64°, respectively. By optimizing the symmetry-independent dimer molecules, the rotational barrier between the conformers is found to be within the 2.5-5.5 kcal/mol range. QTAIM and RDG based NCI isosurface revealed the presence of strong N-H…N and C-H…O hydrogen bonds which stabilize the two independent centrosymmetric inversion-related dimers. Further, weak and short directional interactions such as C-H…N, H…H and C-H…π were also analyzed systematically using various topological parameters. The compound is found to adhere to the Lipinski's rule of five and exhibit good pharmacokinetic properties. The results of molecular docking studies performed against SARS-CoV-2 virus main protease (PDB IDs: 6LU7, 6W9C and 6WQF) revealed that the compound showed better docking scores. Molecular docking studies verified the inhibition activity of the synthesized novel compound. Finally, the binding free energy and contributed energies were calculated using MM-GBSA method. The 6LU7-ligand complex showed highest binding free energy and among all other interactions, the contributions of the covalent binding and van der Waals energy are found to be significant.Communicated by Ramaswamy H. Sarma.

Synthesis of Sulfoximines and Sulfonimidamides Using Hypervalent Iodine Mediated NH Transfer

The development of NH transfer reactions using hypervalent iodine and simple sources of ammonia has facilitated the synthesis of sulfoximines and sulfonimidamides for applications across the chemical sciences. Perhaps most notably, the methods have been widely applied in medicinal chemistry and in the preparation of biologically active compounds, including in the large-scale preparation of an API intermediate. This review provides an overview of the development of these synthetic methods involving an intermediate iodonitrene since our initial report in 2016 on the conversion of sulfoxides into sulfoximines. This review covers the NH transfer to sulfoxides and sulfinamides, and the simultaneous NH/O transfer to sulfides and sulfenamides to form sulfoximines and sulfonimidamides, respectively. The mechanism of the reactions and the identification of key intermediates are discussed. Developments in the choice of reagents, and in the reaction conditions and setups used are described.

Iodonitrene: a direct metal-free electrophilic aminating reagent

Iodonitrene is a new type of reactive electrophilic aminating reagent that opens up opportunities for new discoveries.

Synthesis and Transformations of NH-Sulfoximines

Recent years have seen a marked increase in the occurrence of sulfoximines in the chemical sciences, often presented as valuable motifs for medicinal chemistry. This has been prompted by both pioneering works taking sulfoximine containing compounds into clinical trials and the concurrent development of powerful synthetic methods. This review covers recent developments in the synthesis of sulfoximines concentrating on developments since 2015. This includes extensive developments in both S-N and S-C bond formations. Flow chemistry processes for sulfoximine synthesis are also covered. Finally, subsequent transformations of sulfoximines, particularly in N-functionalization are reviewed, including N-S, N-P, N-C bond forming processes and cyclization reactions.

Cubane, Bicyclo[1.1.1]pentane and Bicyclo[2.2.2]octane: Impact and Thermal Sensitiveness of Carboxyl-, Hydroxymethyl- and Iodo-substituents

With the burgeoning interest in cage motifs for bioactive molecule discovery, and the recent disclosure of 1,4-cubane-dicarboxylic acid impact sensitivity, more research into the safety profiles of cage scaffolds is required. Therefore, the impact sensitivity and thermal decomposition behavior of judiciously selected starting materials and synthetic intermediates of cubane, bicyclo[1.1.1]pentane (BCP), and bicyclo[2.2.2]octane (BCO) were evaluated via hammer test and sealed cell differential scanning calorimetry, respectively. Iodo-substituted systems were found to be more impact sensitive, whereas hydroxymethyl substitution led to more rapid thermodecomposition. Cubane was more likely to be impact sensitive with these substituents, followed by BCP, whereas all BCOs were unresponsive. The majority of derivatives were placed substantially above Yoshida thresholds-a computational indicator of sensitivity.