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.

Oxidative Nitrogen Insertion into Silyl Enol Ether C═C Bonds

Here, we demonstrate a fundamentally new reactivity of the silyl enol ether functionality utilizing an in situ-generated iodonitrene-like species. The present transformation inserts a nitrogen atom between the silyl enol ether olefinic carbons with the concomitant cleavage of the C═C bond. Overall, this facile transformation converts a C-nucleophilic silyl enol ether to the corresponding C-electrophilic N-acyl-N,O-acetal. This unprecedented access to α-amido alkylating agents enables modular derivatization with carbon and heteroatom nucleophiles and the unique late-stage editing of carbon frameworks. The reaction efficiency of this transformation is well correlated with enol ether nucleophilicity as described by the Mayr N scale. Applications presented herein include late-stage nitrogen insertion into carbon skeletons of natural products with previously unattainable regioselectivity as well as modified conditions for 15N labeling of amides and lactams.

Electrochemically Enable N-Sulfenylation/Phosphinylation of Sulfoximines via Oxidative Dehydrocoupling Reaction

An electrochemical oxidative cross-coupling strategy for the synthesis of N-sulfenylsulfoximines from sulfoximines and thiols was accomplished, giving diverse N-sulfenylsulfoximines in moderate to good yields. Moreover, this strategy can be extended to construct the N-P bond of N-phosphinylated sulfoximines. With electrons as reagents, the oxidative dehydrogenation cross-coupling reaction proceeds smoothly in the absence of traditional redox reagents.

Modular Synthesis of 1,2-Benzothiazines and 1,2-Benzothiazine 1-Imines via Palladium-Catalyzed C-H/C-C Activation Reactions

In this study, a modular approach toward cyclic sulfoximines and sulfondiimines via palladium-catalyzed intramolecular C-H/C-C activation reactions was reported. Various 1,2-benzothiazines including bicyclic, tricyclic, highly fused ones, ones of the seven-membered ring, along with 1,2-benzothiazine 1-imines were accessed in good yields. KIE experiment demonstrated that the C-H bond cleavage at the position ortho to the sulfoximine group is not the rate-determining step in the coupling reaction.

Synthesis of Pyrazolesulfoximines Using α-Diazosulfoximines with Alkynes

Sulfoximines and pyrazoles are both important motifs in medicinal compounds. Here we report the synthesis and reactivity of sulfoximine diazo compounds as new reagents for the incorporation of sulfoximines. The use of N-silyl sulfoximines enabled formation of monosubstituted diazo compounds. Their application is demonstrated in a [3 + 2] cycloaddition with alkynes to form pyrazole sulfoximines in a new combination of these important chemotypes. Further derivatization of the pyrazole sulfoximines is demonstrated, including silyl deprotection to form unprotected pyrazolesulfoximines.

Electrochemical N-Acylation of Sulfoximine with Hydroxamic Acid

Despite the widespread applications of sulfoximines, green and efficient access to functionalized sulfoximines remains a challenge. By employing an electrochemical strategy, we describe an approach for the construction of N-aroylsulfoximines, which features a broad substrate scope, mild reaction conditions, safety on a gram scale, and no need for an external oxidant and transition metal catalysts.

Phenotypic screening identifies a trisubstituted imidazo[1,2-a]pyridine series that induces differentiation in multiple AML cell lines

Acute myeloid leukaemia (AML) is an aggressive type of leukaemia with low rates of long-term survival. While the current standard of care is based on cytotoxic chemotherapy, a promising emerging approach is differentiation therapy. However, most current differentiating agents target specific mutations and are effective only in certain patient subtypes. To identify agents which may be effective in wider population cohorts, we performed a phenotypic screen with the myeloid marker CD11b and identified a compound series that was able to differentiate AML cell lines in vitro regardless of their mutation status. Structure-activity relationship studies revealed that replacing the formamide and catechol methyl ether groups with sulfonamide and indazole respectively improved the in vitro metabolic profile of the series while maintaining the differentiation profile in multiple cell lines. This optimisation exercise enabled progression of a lead compound to in vivo efficacy testing. Our work supports the promise of phenotypic screening to identify novel small molecules that induce differentiation in a wide range of AML subtypes.

Fluoroalkyl Sulfoximines for Versatile Photocatalytic Radical Fluoroalkylations

Fluoroalkyl sulfoximines, which serve as electron-accepting fluoroalkyl radical sources, are easy-to-handle, solid, and bench-stable chemicals. Fluoroalkyl radicals can be generated from sulfoximine reagents using strong one-electron injectors, such as a highly reducing photoredox catalyst in the excited state. Our group has developed photocatalytic radical di- and mono-fluoromethylation and α-monofluoroalkylation of olefins with the corresponding fluoroalkyl sulfoximines. In this personal account, appropriate combinations of fluoroalkyl sulfoximines and photoredox catalysts, leading to successful radical fluoroalkylation, have been discussed.

Iridium(III)-Catalyzed C-H Cyclization of Sulfoximines with Diazo Meldrum's Acids for the Synthesis of Cyclic Sulfoximines

Iridium(III)-catalyzed C-H cyclization of sulfoximines with diazo Meldrum's acid provided cyclic sulfoximines with a carbonyl group in good to excellent yields. These compounds were easily converted into unsubstituted and arylated sulfoximines. Moreover, the vinyl triflates obtained from the cyclic sulfoximines underwent palladium(II)-catalyzed cross-coupling reactions with a variety of aryl, arylalkynyl, and heteroatom (N and S) nucleophiles, affording a wide range of monosubstituted sulfoximines in high yields.

Nitrogen atom insertion into indenes to access isoquinolines

We report a convenient protocol for a nitrogen atom insertion into indenes to afford isoquinolines. The reaction uses a combination of commercially available phenyliodine(iii) diacetate (PIDA) and ammonium carbamate as the nitrogen source to furnish a wide range of isoquinolines. Various substitution patterns and commonly used functional groups are well tolerated. The operational simplicity renders this protocol broadly applicable and has been successfully extended towards the direct interconversion of cyclopentadienes into the corresponding pyridines. Furthermore, this strategy enables the facile synthesis of ¹⁵N labelled isoquinolines, using ¹⁵NH₄Cl as a commercial ¹⁵N source.

A rapid and selective methionine oxidative modification strategy

Considering the fact that site-selective late-stage diversification of peptides and proteins remains a challenge for biochemistry, strategies targeting low-abundance natural amino acids need to be further developed. As an extremely oxidation-sensitive and low-abundance amino acid, methionine emerges as a promising target for chemo- and site-selective modification. Herein we report an efficient and highly selective modification on methionine residues by one-pot O- and N-transfer reaction, generating sulfoximine-modified peptides with near-perfect conversion within 10 min. Moreover, the great tolerance to other natural amino acids has been demonstrated in reactions with various peptide substrates. To demonstrate the generality of this protocol, we have modified natural peptides and obtained sulfoximination products with high conversion rates. This methodology provides a novel strategy as the expansion of the methionine-based peptide functionalization toolbox.

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.

Synthesis of Sulfoximine Propargyl Carbamates under Improved Conditions for Rhodium Catalyzed Carbamate Transfer to Sulfoxides

Sulfoximines provide aza-analogues of sulfones, with potentially improved properties for medicinal chemistry. The sulfoximine nitrogen also provides an additional vector for the inclusion of other functionality. Here, we report improved conditions for rhodium catalyzed synthesis of sulfoximine (and sulfilimine) carbamates, especially for previously low-yielding carbamates containing π-functionality. Notably we report the preparation of propargyl sulfoximine carbamates to provide an alkyne as a potential click handle. Using Rh₂(esp)₂ as catalyst and a DOE optimization approach provided considerably increased yields.

Copper-Catalyzed, Aerobic Synthesis of NH-Sulfonimidamides from Primary Sulfinamides and Secondary Amines

NH-Sulfonimidamides are prepared by copper-catalyzed coupling of primary sulfinamides with secondary amines. Neither a ligand nor an additive is needed, and air is the terminal oxidant. The reactions occur at room temperature, show good functional group tolerance, and lead to products in good yields. A sulfanenitrile is proposed as an intermediate in this oxidative amination.

Late-stage diversification of indole skeletons through nitrogen atom insertion

Compared with peripheral late-stage transformations mainly focusing on carbon-hydrogen functionalizations, reliable strategies to directly edit the core skeleton of pharmaceutical lead compounds still remain scarce despite the recent flurry of activity in this area. Herein, we report the skeletal editing of indoles through nitrogen atom insertion, accessing the corresponding quinazoline or quinoxaline bioisosteres by trapping of an electrophilic nitrene species generated from ammonium carbamate and hypervalent iodine. This reactivity relies on the strategic use of a silyl group as a labile protecting group that can facilitate subsequent product release. The utility of this highly functional group-compatible methodology in the context of late-stage skeletal editing of several commercial drugs is demonstrated.

Improving Aqueous Solubility and In Vitro Pharmacokinetic Properties of the 3-Nitroimidazo[1,2-a]pyridine Antileishmanial Pharmacophore

An antileishmanial structure−activity relationship (SAR) study focused on positions 2 and 8 of the imidazo[1,2-a]pyridine ring was conducted through the synthesis of 22 new derivatives. After being screened on the promatigote and axenic amastigote stages of Leishmania donovani and L. infantum, the best compounds were tested against the intracellular amastigote stage of L. infantum and evaluated regarding their in vitro physicochemical and pharmacokinetic properties, leading to the discovery of a new antileishmanial6-chloro-3-nitro-8-(pyridin-4-yl)-2-[(3,3,3-trifluoropropylsulfonyl)methyl]imidazo[1,2-a]pyridine hit. It displayed low cytotoxicities on both HepG2 and THP1 cell lines (CC50 > 100 µM) associated with a good activity against the intracellular amastigote stage of L. infantum (EC50 = 3.7 µM versus 0.4 and 15.9 µM for miltefosine and fexinidazole, used as antileishmanial drug references). Moreover, in comparison with previously reported derivatives in the studied series, this compound displayed greatly improved aqueous solubility, good mouse microsomal stability (T1/2 > 40 min) and high gastrointestinal permeability in a PAMPA model, making it an ideal candidate for further in vivo studies on an infectious mouse model.

Synthesis of Enantioenriched Primary tert-Butanesulfonimidamides via Imination-Hydrazinolysis of N'-tert-Butanesulfinyl Amidines

The first synthesis of primary tert-butanesulfonimidamides with high enantiopurity was realized by imination (or imination/N-functionalization) of enantioenriched N'-tert-butanesulfinyl amidines, followed by hydrazinolysis. N'-Sulfinyl amidines served as imination precursors during copper-catalyzed sulfonyl nitrene transfer or iodonitrene-based NH transfer. Further transformations allowed access to primary tert-butanesulfonimidamides with diverse substitutions on the nitrogen of S═N.

Transition metal-free, base mediated one-pot approach for the construction of the benzo[b][1,4,5]oxathiazepine 1-oxide core

Protocol for synthesising selected separable diastereomers of benzo[b][1,4,5]oxathiazepine 1-oxides via intermolecular epoxide ring opening by o-halogenated NH-sulfoximine followed by cyclisation and configurations were assigned by 2D NMR and X-ray crystallography.

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.

14N NMR as a General Tool to Characterize the Nitrogen-Containing Species and Monitor the Nitration Process

The usefulness of ¹⁴N NMR spectroscopy was highly underestimated compared with ¹⁵N NMR, which usually required tedious and expensive ¹⁵N-labeling manipulations. It is of great significance to make the ¹⁴N NMR spectroscopy convenient and useful considering ¹⁴N nuclei's high natural abundance of 99.6%. Herein, lots of efforts have been made to generalize routine ¹⁴N NMR to characterize nitrogen-containing species by tuning the balance between the solubility and viscosity of the samples. Satisfactory ¹⁴N NMR spectra of more than 60 nitrogen-containing compounds have been recorded, and the chemical shifts and the peaks' full width at half-maxima of more than 10 nitrogen-based functionalities have been summarized. Successful monitoring of the ortho-selective nitration of aniline has been demonstrated using the ¹⁴N NMR protocol developed in this paper, which will help realize the visualization of nitration processes in the industry.

Synthesis of Six-Membered N-Heterocycle Frameworks Based on Intramolecular Metal-Free N-Centered Radical Chemistry

The formation of intramolecular C-N bond represents a powerful strategy in organic transformation as the great importance of N-heterocycles in the fields of natural products and bioactive molecules. This personal account describes the synthesis of cyclic phosphinamidation, benzosultam, benzosulfoximine, phenanthridine and their halogenated compounds through transition-metal-free intramolecular oxidative C-N bond formation. Mechanism study reveals that N-X bond is initially formed under the effect of hypervalent halogen, which is very unstable and easily undergoes thermal or light homolytic cleavage to generate nitrogen radical. Then the nitrogen radical is trapped by the arene to give aryl radical. Rearomatization of aryl radical under the oxidant to provide corresponding N-heterocycle. Under suitable conditions, the N-heterocycles can be further transformed to halogenated N-heterocycles.

Electrochemical Oxidative Syntheses of NH-Sulfoximines, NH-Sulfonimidamides and Dibenzothiazines via Anodically Generated Hypervalent Iodine Intermediates

Herein, we report a general method for the synthesis of NH-sulfoximines and NH-sulfonimidamides through direct electrochemical oxidative catalysis involving an iodoarene(I)/iodoarene(III) redox couple. In addition, dibenzothiazines can be synthesized from [1,1'-biaryl]-2-sulfides under standard conditions. Notably, only a catalytic amount of iodoarene is required for the generation in situ of an active hypervalent iodine catalyst, which avoids the need for an excess of a hypervalent iodine reagent relative to conventional approaches. Moreover, this protocol features broad substrate scope and wide functional group tolerance, delivering the target compounds with good-to-excellent yields even for a scale of more than 10 g.

Structure and Reactivity of N-Heterocyclic Alkynyl Hypervalent Iodine Reagents

Ethynylbenziodoxol(on)e (EBX) cyclic hypervalent iodine reagents have become popular reagents for the alkynylation of radicals and nucleophiles, but only offer limited possibilities for further structure and reactivity fine-tuning. Herein, the synthesis of new N-heterocyclic hypervalent iodine reagents with increased structural flexibility based on amide, amidine and sulfoximine scaffolds is reported. Solid-state structures of the reagents are reported and the analysis of the I-Calkyne bond lengths allowed assessing the trans-effect of the different substituents. Molecular electrostatic potential (MEP) maps of the reagents, derived from DFT computations, revealed less pronounced σ-hole regions for sulfonamide-based compounds. Most reagents reacted well in the alkynylation of β-ketoesters. The alkynylation of thiols afforded more variable yields, with compounds with a stronger σ-hole reacting better. In metal-mediated transformations, the N-heterocyclic hypervalent iodine reagents gave inferior results when compared to the O-based EBX reagents.

Synthesis and Configurational Assignment of Vinyl Sulfoximines and Sulfonimidamides

Vinyl sulfones and sulfonamides are valued for their use as electrophilic warheads in covalent protein inhibitors. Conversely, the S(VI) aza-isosteres thereof, vinyl sulfoximines and sulfonimidamides, are far less studied and have yet to be applied to the field of protein bioconjugation. Herein, we report a range of different synthetic methodologies for constructing vinyl sulfoximine and vinyl sulfonimidamide architectures that allows access to new areas of electrophilic chemical space. We demonstrate how late-stage functionalization can be applied to these motifs to incorporate alkyne tags, generating fully functionalized probes for future chemical biology applications. Finally, we establish a workflow for determining the absolute configuration of enantioenriched vinyl sulfoximines and sulfonimidamides by comparing experimentally and computationally determined electronic circular dichroism spectra, enabling access to configurationally assigned enantiomeric pairs by separation.

Photochemistry of N-Phenyl Dibenzothiophene Sulfoximine†

Sulfoximines are popular scaffolds in drug discovery due to their hydrogen bonding properties and chemical stability. In recent years, the role of reactive intermediates such as nitrenes has been studied in the synthesis and degradation of sulfoximines. In this work, the photochemistry of N-phenyl dibenzothiophene sulfoximine [5-(phenylimino)-5H-5λ⁴ -dibenzo[b,d]thiophene S-oxide] was analyzed. The structure resembles a combination of N-phenyl iminodibenzothiophene and dibenzothiophene S-oxide, which generate nitrene and O(³ P) upon UV-A irradiation, respectively. The photochemistry of N-phenyl dibenzothiophene sulfoximine was explored by monitoring the formation of azobenzene, a photoproduct of triplet nitrene, using direct irradiation and sensitized experiments. The reactivity profile was further studied through direct irradiation experiments in the presence of diethylamine (DEA) as a nucleophile. The studies demonstrated that N-phenyl dibenzothiophene sulfoximine underwent S-N photocleavage to release singlet phenyl nitrene which formed a mixture of azepines in the presence of DEA and generated moderate amounts of azobenzene in the absence of DEA to indicate formation of triplet phenyl nitrene.

One-Pot Synthesis of N-Iodo Sulfoximines from Sulfides

This is the first report on the synthesis and characterization of N-iodo sulfoximines. The synthesis was designed as a room temperature one-pot cascade reaction from readily available sulfides as starting compounds, converted into sulfoximines by reaction with ammonium carbonate and (diacetoxyiodo)benzene, followed by iodination with N-iodosuccinimide or iodine in situ, in up to 90% isolated yields, also at a multigram scale. Iodination of aryls with N-iodo sulfoximines, oxidation, and conversion to N-SCF₃ congeners have been demonstrated.

Hydroxylamine-Derived Reagent as a Dual Oxidant and Amino Group Donor for the Iron-Catalyzed Preparation of Unprotected Sulfinamides from Thiols

An iron catalyzed reaction for the selective transformation of thiols (-SH) to sulfinamides (-SONH2 ) by a direct transfer of -O and free -NH2 groups has been developed. The reaction operates under mild conditions using a bench stable hydroxylamine derived reagent, exhibits broad functional group tolerance, is scalable and proceeds without the use of any precious metal catalyst or additional oxidant. This novel, practical reaction leads to the formation of two distinct new bonds (S=O and S-N) in a single step to chemoselectively form valuable, unprotected sulfinamide products. Preliminary mechanistic studies implicate the role of the alcoholic solvent as an oxygen atom donor.

Synthesis of Sulfinamidines and Sulfinimidate Esters by Transfer of Nitrogen to Sulfenamides

In this work we report a new synthetic tactic for the straightforward preparation of hardly accessible sulfinamidines and sulfinamide esters, by using a simple metal-free protocol. The process is robust and uses readily available sulfenamides as the S-donor and sulfonyloxycarbamates as the N-source. The scope and mechanism have also been investigated.

Harnessing Sulfinyl Nitrenes: A Unified One-Pot Synthesis of Sulfoximines and Sulfonimidamides

Sulfoximines and sulfonimidamides are promising compounds for medicinal and agrochemistry. As monoaza analogues of sulfones and sulfonamides, respectively, they combine good physicochemical properties, high stability, and the ability to build complexity from a three-dimensional core. However, a lack of quick and efficient methods to prepare these compounds has hindered their uptake in molecule discovery programmes. Herein, we describe a unified, one-pot approach to both sulfoximines and sulfonimidamides, which exploits the high electrophilicity of sulfinyl nitrenes. We generate these rare reactive intermediates from a novel sulfinylhydroxylamine (R–O–N=S=O) reagent through an N–O bond fragmentation process. Combining sulfinyl nitrenes with carbon and nitrogen nucleophiles enables the synthesis of sulfoximines and sulfonimidamides in a reaction time of just 15 min. Alkyl, (hetero)aryl, and alkenyl organometallic reagents can all be used as the first or second component in the reaction, while primary and secondary amines, and anilines, all react with high efficiency as the second nucleophile. The tolerance of the reaction to steric and electronic factors has allowed for the synthesis of the most diverse set of sulfoximines and sulfonimidamides yet described. Experimental and computational investigations support the intermediacy of sulfinyl nitrenes, with nitrene formation proceeding via a transient triplet intermediate before reaching a planar singlet species.

Modern Stereoselective Synthesis of Chiral Sulfinyl Compounds

Chiral sulfinyl compounds, sulfoxides, sulfoximines, sulfinamides, and other derivatives, play an important role in asymmetric synthesis as versatile auxiliaries, ligands, and catalysts. They are also recognized as pharmacophores found in already marketed and well-sold drugs (e.g., esomeprazole) and used in drug design. This review is devoted to the modern methods of preparation of sulfinyl derivatives in enantiopure or enantiomerically enriched form. Selected new approaches leading to racemic products for which the asymmetric variant can be developed in the future are mentioned as well.

Selective Synthesis of N-Cyano Sulfilimines by Dearomatizing Stable Thionium Ions

For the selective synthesis of N-cyano sulfilimines, we have developed a new method based on the soft-soft interaction between thionium ion electrophiles and cyanonitrene nucleophiles. The stable thionium ion was successfully obtained by oxidative dearomatization using phenyliodine (III) diacetate (PIDA) in N,N-dimethylformamide (DMF). The sulfur imination reactions were tolerant to a wide range of functional groups and exhibited high selectivities and excellent yields. The existence of thionium ion intermediates was confirmed by ultraviolet/visible (UV/vis) spectroscopy and ¹H NMR experiments.

Increasing Complexity: A Practical Synthetic Approach to Three-Dimensional, Cyclic Sulfoximines and First Insights into Their in Vitro Properties

A short synthetic approach with broad scope to access five- to seven-membered cyclic sulfoximines in only two to three steps from readily available thiophenols is reported. Thus, simple building blocks were converted to complex molecular structures by a sequence of S-alkylation and one-pot sulfoximine formation, followed by intramolecular cyclization. Seventeen structurally diverse cyclic sulfoximines were prepared in high overall yields. In vitro evaluation of these underrepresented, three-dimensional, cyclic sulfoximines with respect to properties relevant to medicinal chemistry did not reveal any intrinsic flaw for application in drug discovery.

Synthesis of NH-Sulfoximines by Using Recyclable Hypervalent Iodine(III) Reagents under Aqueous Micellar Conditions

The synthesis of NH-sulfoximines from sulfides has been first developed under mild conditions in an aqueous solution with surfactant TPGS-750-M as the catalyst at room temperature. In this newly developed process, a simple and convenient recycling strategy to regenerate the indispensable hypervalent iodine(III) is used. The resulting 1,2,3-trifluoro-5-iodobezene can be recovered almost quantitively from the mixture by liquid-liquid extraction and then oxidized to give the corresponding iodine(III) species. This optimized procedure is compatible with a broad range of functional groups and can be easily performed on a gram scale, providing a green protocol for the synthesis of sulfoximines.

Design of iodinated radioligands for SPECT imaging of central human 5-HT4R using a ligand lipophilicity efficiency approach

A series of iodinated ligands for the SPECT imaging of 5-HT₄ receptors was designed starting from the previously reported hit MR-26132. We focused on the modulation of the piperidine-containing lateral chain by introducing hydrophilic groups in order to decrease the liphophilicity of the new ligands. All the synthesized compounds were tested for their binding affinities on 5-HT₄Rs and based on the Ligand Lipophilicity Efficiency approach, compound 13 was further selected for radioiodination with iodine-125 and imaging experiments. Compound 13 showed its ability to displace the specific signal of the reference compound [¹²⁵I]SB-207710 but no significant detection of [¹²⁵I]13 was observed in vivo in SPECT experiments.

Synthesis of glycosyl sulfoximines by a highly chemo- and stereoselective NH- and O-transfer to thioglycosides

The first highly stereoselective sulfoximine formation directly from sulfides is achieved in the preparation of unprecedented glycosyl sulfoximines. X-ray analysis and a computational model establish the configuration at sulfur.